Biomedical subjects

M Haude

Publications and source records attributed to M Haude.

At least 55 records · Page 3Linked to original sources

PubMed2000

Safety of intracoronary Doppler flow measurement.

BACKGROUND: With the introduction of Doppler-tipped guide wires, intracoronary Doppler flow measurement has been increasingly accepted as an additional diagnostic approach in the catheterization laboratory. However, the safety of intracoronary Doppler flow measurement has not been well-investigated. The purpose of our study was to evaluate the safety of intracoronary Doppler flow measurement using the Doppler FloWire (Cardiometrics, Mountain View, Calif). METHODS AND RESULTS: A total of 906 patients were examined by intracoronary Doppler with a 0.014-inch or an 0.018-inch Doppler FloWire. For coronary flow reserve measurement, intracoronary injection of adenosine or papaverine was used. Of the patients studied, 77 were cardiac transplant recipients and 829 were patients who had not received a transplant, of whom 617 had undergone diagnostic coronary procedures and 212 had coronary interventions. In 27 (2.98%) of 906 patients adverse cardiac events were observed. Fifteen (1.66%) of 906 patients had severe transient bradycardia develop (asystole or second- to third-degree atrioventricular block) after intracoronary administration of adenosine, 14 of which occurred in the right coronary artery and 1 in the left anterior descending artery. Nine (0.99%) of 906 patients had coronary spasm during the passage of the Doppler wire (5 in the right coronary artery, 4 in the left anterior descending artery). Two (0.22%) of 906 patients had ventricular fibrillation during the procedure. Hypotension with bradycardia and ventricular extrasystole each occurred in 1 (0.11%) of 906 patients. The incidence of complication was significantly higher in transplant recipients than in patients who underwent either diagnostic or interventional procedures (12.99% vs 2.43% vs 0.94%, P <.001). The Doppler measurements in the right coronary artery were associated with a higher incidence of complications, especially bradycardia, compared with the left anterior descending and the left circumflex arteries (right coronary, 5.87% vs left anterior descending, 1.05% vs left circumflex, 0.17%; P <.001). All complications were cured medically. CONCLUSION: Intracoronary Doppler flow measurement with Doppler wires and intracoronary administration of adenosine is a safe method. However, severe complications such as bradycardia and coronary spasm can occur. Attention should be paid to the examination of the right coronary artery, especially in heart transplant recipients.

Adenosine↗

PubMed2000

Immediate stent implantation versus conventional techniques for the treatment of abrupt vessel closure or symptomatic dissections after coronary balloon angioplasty.

BACKGROUND: Coronary stenting was initially designed to treat a bailout scenario. Prospective randomized trials comparing stent implantation with standard techniques, including emergency coronary artery bypass grafting, are lacking. The aim of this trial was to test the superiority of immediate stent implantation compared with standard techniques for the treatment of abrupt or threatening closure after coronary balloon angioplasty. METHODS: In a prospective trial, 100 patients with abrupt vessel closure or symptomatic dissections causing objective signs of ischemia were randomly assigned to treatment with immediate placement of stents (n = 51) versus standard techniques such as prolonged dilatation or emergency bypass surgery (n = 49). The primary end point was the achievement of successful stabilization not requiring crossover to the other study group. Secondary end points included event-free survival and restenosis. RESULTS: Successful stabilization was achieved in 94% of patients in the stent group compared with 78% of patients in the standard treatment group (P =.038). Two patients died in each group, and there was a trend toward a higher incidence of myocardial infarction (16% vs 8%; P =.163) and a significantly increased creatine phosphokinase level (245 IU/L [95% confidence interval, 217-265 IU/L] vs 179 IU/L [confidence interval 140-212 IU/L]; P =.0002) in the standard treatment group. Event-free survival after 250 days was 72% in the stent group compared with 29% in the standard treatment group (P =.001). The angiographic restenosis rate was 30% in the stent group versus 59% in the standard treatment group (P =.01). CONCLUSIONS: Immediate stenting, if technically feasible, shows superior short- and long-term results compared with standard treatment options.

Aged↗

PubMed2000

Size of emptied plaque cavity following spontaneous rupture is related to coronary dimensions, not to the degree of lumen narrowing. A study with intravascular ultrasound in vivo.

OBJECTIVE: To identify any potential relations between the size of an emptied plaque cavity and the remodelling pattern, plaque or vessel dimensions, lumen narrowing, and other ultrasonic lesion characteristics. DESIGN: Intravascular ultrasound was used to examine prospectively 51 ruptured ulcerated coronary plaques. Cross sectional area measurements comprised lumen, vessel, plaque, and emptied plaque cavity. Lumen narrowing was calculated as 1 - (lesion lumen area/reference lumen area) x 100%. A remodelling index was calculated as lesion vessel area/reference vessel area, and plaques were divided into those with values > 1.05 (group A) and </= 1.05 (group B). RESULTS: Of the total of 51 plaques, 36 (71%) were assigned to group A and 15 (29%) to group B. In neither group was there a significant difference in reference dimensions and lumen narrowing. However, lesion vessel (mean (SD): 22.6 (8.1) mm(2) v 17. 5 (4.3) mm(2); p = 0.006) and plaque areas (15.8 (6.2) mm(2) v 12.8 (3.2) mm(2); p = 0.03) were greater in group A than in group B. The cavity inside the plaque was larger in group A than in group B (2.8 (1.6) mm(2) v 1.8 (0.9) mm(2); p = 0.007) and showed a positive linear relation with lesion and reference vessel size (r = 0.58 and 0.56, respectively; p < 0.001), but not with lumen narrowing. CONCLUSIONS: The size of the emptied cavity inside ruptured plaques is on average larger in lesions with adaptive vascular remodelling, and shows a linear relation with lesion plaque and vessel size and with the reference dimensions, but not with the degree of lumen narrowing.

Adult↗

PubMed1999

G protein beta3 subunit 825T allele and enhanced coronary vasoconstriction on alpha(2)-adrenoceptor activation.

Recently, alpha(2)-adrenoceptor activation was shown to play an important role in the vasoconstriction of normal coronary arteries, whereas in the presence of atherosclerosis, the activation of both alpha(1)- and alpha(2)-adrenoceptors reduces coronary blood flow in humans. alpha(2)-Adrenoceptors activate pertussis toxin (PTX)-sensitive G proteins, whereas alpha(1)-adrenoceptors couple to PTX-insensitive G proteins. Thus, the 825T allele of the beta3 subunit of heterotrimeric G proteins, associated with enhanced PTX-sensitive G protein signaling, was expected to determine the alpha(2)-adrenoceptor-, but not the alpha(1)-adrenoceptor-, mediated reduction in coronary blood flow (CBF). Genotyping was performed on 48 individuals. Twelve of the 48 received the alpha(1)-adrenoceptor agonist methoxamine (MTX; 5 mg IC), and 12 received the alpha(2)-adrenoceptor agonist BHT 933 (BHT; 5 mg IC). Twenty-four additional individuals received both MTX and BHT during the same investigational procedure. CBF was calculated on the basis of coronary angiography and intracoronary Doppler flow velocity measurement. Drug-related ischemia was assessed on the basis of ST-segment changes and angina pectoris. In response to BHT, but not to MTX, CBF was reduced to a significantly greater extent in 825T allele carriers (58+/-4%, n=16) than in individuals homozygous for the C825 allele (28+/-4%, n=19, P=0.001). This finding was independent of cholesterol levels, mean arterial blood pressure, and the presence or absence of coronary artery disease. Ischemic events in response to BHT occurred more frequently in 825T allele carriers than in homozygous 825C allele carriers (P=0.01). alpha(2)-Adrenoceptor coronary vasoconstriction is genetically determined and significantly enhanced in GNB3 825T allele carriers.

Adrenergic alpha-Agonists↗

PubMed1999

Augmented alpha-adrenergic constriction of atherosclerotic human coronary arteries.

BACKGROUND: Although adrenergic activation plays a major role in the initiation of experimental myocardial ischemia, the significance of alpha-adrenergic coronary constriction in humans has been questioned. The present study assessed the impact of selective alpha-adrenergic receptor activation in patients with normal or atherosclerotic coronary arteries. METHODS AND RESULTS: In 39 patients, coronary blood flow (CBF, mL/min) was determined from combined angiography and Doppler measurements. In 8 patients with normal coronary arteries (group 1) and 9 with single coronary artery stenosis (group 2), doses of 1, 2.5, 5, and 10 mg IC of the alpha1-agonist methoxamine (M) were injected. Identical doses of the alpha2-agonist BHT933 (B) were injected in 8 patients with normal coronary arteries (group 3) and 8 with single stenosis (group 4). In 6 additional patients with single stenosis (group 5), aortocoronary sinus lactate differences were measured in response to M and B. CBF remained unchanged in group 1. In contrast, CBF was decreased dose-dependently in group 2, with a maximum at 10 mg M (39.0+/-9.4 versus 15.2+/-7.0). In groups 3 and 4, CBF was also decreased dose-dependently, with a maximum at 10 mg B (63.3+/-24.8 versus 49. 1+/-27.9 and 41.5+/-19.0 versus 12.7+/-8.0, respectively). In group 5, there was more net lactate production with B than with M (-0. 34+/-0.11 versus -0.04+/-0.09 mmol/L). CONCLUSIONS: In normal coronary arteries, alpha1-adrenergic activation does not reduce CBF, whereas alpha2-adrenergic activation reduces CBF by microvascular constriction. Both alpha1- and alpha2-adrenergic epicardial and microvascular constriction are augmented by atherosclerosis and can induce myocardial ischemia.

Adrenergic alpha-Agonists↗

PubMed1999

Stepwise intravascular ultrasound (IVUS) guidance of high-pressure coronary stenting does not result in an improved acute or long-term outcome: a randomized comparison to "final-look" IVUS assessment.

The objective of this study was to evaluate the potential benefit of stepwise intravascular ultrasound (IVUS)-guided coronary stent deployment compared to angiographic stent implantation with final IVUS assessment only. Acute procedural success and 6-month angiographic follow-up were compared in both groups. Intravascular ultrasound was performed using a 20- or 30-MHz mechanically rotated catheter in 85 patients who were prospectively randomized to group A (n=42; IVUS-guided) and group B (n=43; angiography +/- final IVUS assessment). There was no difference in the number of stents implanted (1.5+/-0.9 stents/lesion in group A and 1.3+/-0.6 stents/lesion in group B), the duration of the procedure, or the amount of contrast medium used. Defined criteria of optimal stent deployment (stent apposition, stent symmetry, complete coverage of dissections, >90% in-stent lumen area/reference lumen area) were achieved in 54.2% in group A and 56.6% in group B (NS). Angiographic follow-up was 87.1% at 6+/-2 months, and clinical follow-up was 100% at 8+/-1 months. There was no significant difference in restenosis rate (33.3% vs. 34.9%) applying a binary >50% diameter stenosis criterion for both groups. There was no significant difference in minimal in-stent lumen area at both baseline (7.91+/-2.64 mm2 vs. 7.76+/-2.21 mm2) and follow-up (5.84+/-2 mm2 vs. 5.52+/-1.87 mm2). With regard to immediate procedural lumen gain and rate of restenosis, multiple IVUS examinations during the procedure showed no advantage compared to final IVUS assessment only.

Coronary Angiography↗

PubMed1999

Early clinical experience with the implantation of a novel synthetic coronary stent graft.

Coating stents with autologous venous grafts has been suggested to prevent problems associated with conventional stenting, but the need for surgical vessel harvest hampered broad application. A novel synthetic coronary stent graft (CSG) overcomes this limitation by a synthetic membrane, fixed between two thin metallic stents. We successfully implanted 21 CSGs in 18 patients for treatment of acute coronary rupture, thrombus-containing lesions, and lesions with plaque rupture or adjacent pseudoaneurysm. Substantial residual angiographic diameter stenoses were seen in seven CSGs (25% +/- 10% vs. 8% +/- 6%; P < 0.01), which were implanted with relatively small balloon catheters (balloon-to-artery ratio 1.00 +/- 0.09 vs. 1.24 +/- 0.18; P = 0.01) and required postdilatation. Overall, the largest balloon catheter applied measured 4.0 +/- 0.7 mm (balloon-to-artery ratio 1.21 +/- 0.20) and the inflation pressure was 16 +/- 3 atm. Final intravascular ultrasound imaging demonstrated adequate and symmetrical expansion of the CSG (> or = 85% +/- 15% of the reference lumen). Elective implantation was associated with two small non-Q-wave myocardial infarctions, resulting from unavoidable occlusions of side branches. Thus, implantation of CSG is feasible and safe. Adequate expansion can be achieved by the use of relatively large low-compliant balloon catheters inflated with high pressure.

Angioplasty, Balloon, Coronary↗

PubMed1999

Minimally invasive evaluation of coronary stents with electron beam computed tomography: In vivo and in vitro experience.

We sought to describe the value of electron beam computed tomography (EBCT) to detect stent restenoses at follow-up and to identify characteristic EBCT features of coronary stents. Six coronary stents (GRII, Jostent, NIR, PS, Micro, Wiktor) were scanned in vitro (10 1. 5-mm-thick slices, 15-cm FoV, 100-ms AT) before and after inflation with 3.0-, 3.5-, and 4.0-mm balloons to study intensity values and different stent dimensions in comparison to caliper measurements. In 44 patients (60 +/- 10 years, 4 females) we prospectively compared EBCT findings [eight 8-mm-thick slices in the flow mode, 26-cm field of view (FoV), 50 ms acquisition time (AT)] with 6-month angiographic outcome after placement of 86 stents in 49 vessels. For the detection of significant angiographic luminal narrowing (>/=75%) that occurred in 17/49 vessels (35%), we found a sensitivity of 65%, a specificity of 84%, and a positive and negative predictive value of 69% and 82%, respectively. The in vitro data show significant differences in image intensity between the stents and a significant gradual decrease in image intensity with increasing stent diameters. The mean differences between EBCT and caliper measurements for the length and diameter were 0.17 +/- 0.18 mm and -0.32 +/- 0.25mm, respectively. EBCT is currently the only noninvasive technique that allows the assessment of stent dimensions and stent geometry, which may prove useful in patients when intravascular ultrasound cannot be performed. Contrast-enhanced EBCT is a promising tool for minimally invasive stent patency evaluation at follow-up, especially in patients that are unable to exercise. Cathet. Cardiovasc. Intervent. 48:39-47, 1999.

Coronary Angiography↗

PubMed1999

Role of intravascular ultrasound imaging in identifying vulnerable plaques.

UNLABELLED: A plaque that has a large lipid core and a thin fibrous cap may undergo rupture. Once it ruptures, it may lead to thrombus formation and subsequent vessel occlusion. To identify unstable plaques before they rupture is essential for clinical management and patient's prognosis. Intravascular ultrasound (IVUS) opens a new window for the assessment of plaque morphology to identify vulnerable plaques and plaque rupture. We examined 144 patients with angina and ischemic ECG changes using IVUS. Ruptured plaques, characterized by a plaque cavity and a tear on the thin fibrous cap, were identified in 31 patients (group A) of which 23/31 (74%) clinically presented as unstable angina. Plaque rupture was confirmed by injecting contrast medium filling the plaque cavity during IVUS examination. Of the patients without plaque rupture (group B, n = 108), only 19 (18%) had unstable angina. No significant differences between the 2 groups were found concerning the vessel and plaque areas (p > 0.05). The percent stenosis in group A (56.2 +/- 16.5%) was significantly lower than in group B (67.9 +/- 13.4%) (p < 0.001). Area of the plaque cavity in group A (4.1 +/- 3.2 mm2) was significantly larger than the echolucent zone in group B (1.32 +/- 0.79 mm2) (p < 0.001). The plaque cavity/plaque ratio in group A (38.5 +/- 17.1%) was larger than the echolucent area/plaque ratio in group B (11.2 +/- 8.9%) (p < 0.001). The thickness of the fibrous cap in group A (0.47 +/- 0.20 mm) was significantly thinner than that (0.96 +/- 0.94 mm) in group B (p < 0.001). CONCLUSIONS: Plaques seem to be prone to rupture when the echolucent area is larger than 1 mm2, the echolucent area/plaque ratio greater than 20% and the fibrous cap thinner than 0.7 mm. IVUS has the capacity of identifying plaque rupture and vulnerable plaques. This may have potential influence on patients management and therapy.

Adult↗

PubMed1999

Chest pain after coronary interventional procedures. Incidence and pathophysiology.

Chest pain following successful percutaneous coronary interventions is a common problem. Although the development of chest pain after coronary interventions may be of benign character, it is disturbing to patients, relatives and hospital staff. Such pain may be indicative of acute coronary artery closure, coronary artery spasm or myocardial infarction, but may also simply reflect local coronary artery trauma. The distinction between these causes of chest pain is crucial in selecting optimal care. Management of these patients may involve repeat coronary angiography and additional intervention. Commonly, repeat coronary angiography following percutaneous transluminal coronary angioplasty (PTCA) in patients with chest pain demonstrates widely patent lesion sites suggesting that the pain was due to coronary artery spasm, coronary arterial wall stretching or was of non-cardiac origin. As reported by the National Heart, Lung and Blood Institute PTCA Registry, 4.6% of patients after angioplasty have coronary occlusions, 4.8% suffer a myocardial infarction, and 4.2% have coronary spasm. The frequency of chest pain after new device coronary interventions (atherectomy and stenting) seems to be even higher. However, only the minority of patients with post-procedural chest pain have indeed an ischemic event. Therefore, the vast majority of patients have recurrent chest pain without any signs of ischemia. There is some evidence that non-ischemic chest pain after coronary interventions is more common after stent implantation as compared to PTCA (41% vs. 12%). This may be due to the continuous stretching of the arterial wall by the stent as the elastic recoil occurring after PTCA is minimized. In conclusion, chest pain after coronary interventional procedures may potentially be hazardous when due to myocardial ischemia. However, especially after coronary stent placement, cardiologists must consider "stretch pain" due to the overdilation and stretching of the artery caused by the stent in the differential diagnosis. Clinically, it is, therefore, important to recognize that in addition to ischemia-related chest pain other types of chest pain do exist with cardiac origin.

Angina Pectoris↗

PubMed1999

Non-invasive characterization of cardiac microvascular disease by nuclear medicine using single-photon emission tomography.

In about 10 to 30% of patients with typical angina undergoing coronary angiography for suspicion of stenotic coronary artery disease angiographically normal coronary arteries are found. Kemp et al. in 1973 coined the term syndrome X to describe this entity. In a substantial portion of these patients pathologic findings in myocardial scintigraphy are present. Sensitivity and specificity of thallium-201 exercise imaging by visual analysis of images in the presence of significant coronary stenosis is 84 and 88%, respectively. Several investigators have reported abnormal results in radionuclide exercise tests in patients with angiographically normal coronary arteries. Some of these results can be explained by myocardial bridging, vasospasm, left or right bundle branch block, hypertrophic cardiomyopathy, or absorption artifacts. In the majority of cases, however, these abnormalities are not sufficient to explain the scintigraphic findings. Formerly often claimed "false positive", recent studies suggest that endothelial dysfunction might be the reason for the observed perfusion defects. When comparing patients with angiographically unobstructed coronary arteries with and without perfusion defects in stress myocardial perfusion imaging, patients with pathological results show a significantly lower increase of coronary flow after intracoronary injection of the endothelial-dependent vasodilator acetylcholine. Endothelial-independent vasodilation, however, is not impaired in these patients. In addition, intracoronary Doppler measurements reveal that perfusion defects in myocardial scintigraphy only occur if coronary blood flow in this perfusion area is significantly reduced. These results suggest that regional endothelial dysfunction may cause hypoperfusion in myocardial perfusion imaging and underline the important role of the microcirculation in the distribution of radiotracers. Another striking scintigraphic pattern in patients with microvascular angina is the high incidence of reverse redistribution. These perfusion defects, apparent in images obtained 4 hours after exercise stress testing, often cannot be assigned to the perfusion territory of one of the major epicardial vessels. This results in a marked inhomogeneous radionuclide distribution pattern in resting images. The inhomogeneity is associated with a significant reduced resting coronary flow velocity in these patients. As histologically confirmed microvessel disease is often accompanied by slow-flow phenomenon reflecting decreased resting flow velocity, the results suggest that the inhomogeneous perfusion pattern is caused by microvascular dysfunction. Furthermore, the heterogeneity of nuclide distribution supports the hypothesis that endothelial function is not homogeneous in the entire myocardial microcirculation, but varies considerably. In conclusion, microvascular dysfunction by itself seems to cause regional myocardial hypoperfusion, as documented by myocardial scintigraphy. When interpreting pathological scintigraphic results in patients without significant epicardial stenosis, true blood flow and myocardial perfusion abnormalities must be assumed.

Animals↗

PubMed1999

Prevalence of microvascular disease in patients with significant coronary artery disease.

Coronary flow velocity reserve (CFVR) measurement using intracoronary Doppler techniques has been increasing accepted for the assessment of physiological significance of epicardial stenosis and the functional changes after coronary interventions. However, large discrepancy exists concerning the acute changes of CFVR immediately after intervention. The purpose of this study was to investigate the prevalence of microvascular dysfunction in patients with significant coronary artery disease. Intracoronary Doppler flow measurements were performed in a total of 212 patients who underwent coronary interventions because of significant epicardial stenosis using 0.014" Doppler flow wire (Cardiometrics, Inc, Mountain View, CA). Intracoronary bolus injection of adenosine (12 micrograms for the right coronary and 18 micrograms for the left coronary arteries) was used to induce hyperemic reaction. CFVR was registered as the ratio of average peak velocity during hyperemia (hAPV) to at baseline (bAPV). Successful coronary interventions either by percutaneous transluminal coronary balloon angioplasty (PTCA) or by stenting could significantly improve the CFVR. In 80 patients with PTCA, the bAPV elevated from 16.6 +/- 2.1 cm/s to 20.6 +/- 13.4 cm/s and hAPV from 30.1 +/- 15.9 cm/s to 45.2 +/- 17.7 cm/s (both p < 0.001) with PTCA and the CFVR increased from 1.94 +/- 0.78 to 2.58 +/- 0.87 correspondingly (p < 0.001). Significant elevation of coronary flow parameters were also found in 132 patients with subsequent stent implantation (bAPV from 15.3 +/- 6.7 cm/s to 18.7 +/- 9.1 cm/s, hAPV from 28.7 +/- 14.4 cm/s to 44.3 +/- 17.7 cm/s and CFVR from 1.90 +/- 0.70 to 2.59 +/- 0.87, all p < 0.001). Reduction of CFVR (< 3.0) after intervention still existed in 46 (61.3%) of 80 patients after PTCA and 88 (66.7%) of 132 patients after stenting. Moreover, CFVR < 3.0 were found in 50 (45.9%) of 109 reference vessels in patients with single vessel disease. Significant improvement of coronary flow velocity and coronary flow velocity reserve could be obtained after successful angioplasty. However, microvascualr dysfunction existed in a large proportion of patients either in normal reference vessels or in target vessels after interventions.

Adult↗

PubMed1999

[Anti-ischemic effect of verapamil within the scope of interventional recanalization].

We report on a 46-year-old male with unstable angina pectoris due to a total proximal occlusion of the left circumflex artery. At the side of a plaque rupture there was a thrombotic occlusion. With PTCA recanalization was possible, but a dissection occurred, therefore coronary stents were implanted. Besides an optimal morphological result and recurrent applications of nitroglycerin, the baseline blood flow velocity declined from initial 16 cm/s to 11 cm/s after PTCA down to 8.4 cm/s after stent implantation. Because peak flow velocity remained almost unchanged, the low baseline velocity ("slow flow phenomenon") did not lead to an impaired coronary flow velocity reserve (CFVR). Only after application of 1 mg verapamil, a sustained flow velocity on a higher baseline level was reached (17 cm/s), at the same time typical signs of ischemia in the ECG (ST-segment depressions) improved. Additionally, in the non-treated LAD there was an increase in coronary blood flow velocity from 10 cm/s up to 25 cm/s. The reduction in coronary blood flow velocity with increasing manipulations might be due to an impairment of the coronary microcirculations with increasing alpha-adrenergic vasoconstriction, a distribution of vasoactive agents and peripheral microembolizations. Only after administration of verapamil, a calcium channel blocker with non-specific anti-adrenergic effects, the slow flow was removed and ECG signs of ischemia improved. The blood flow velocity in the non-treated LAD was low at baseline and improved after verapamil. This phenomenon leads to the conclusion that mechanisms with vasoconstrictive effect are present in the whole coronary system, but these mechanisms are less pronounced in non-treated vessels.

Angina, Unstable↗

PubMed1999

[Hemostatic closure of arterial puncture site using Angio-Seal after diagnostic heart catheterization or coronary intervention].

Conventional manual compression and subsequent application of pressure bandages is associated with prolonged immobility and significant patient discomfort. Routine anticoagulation as well as the use of new interventional devices and platelet inhibiting strategies lead to a higher incidence of local bleeding complications after diagnostic cardiac catheterization or coronary angioplasty. Immediate sheath removal increases patient comfort. The Angio-Seal system uses a biodegradable anchor and collagen plug for sealing of arterial puncture sites. Several studies showed the safety and efficacy of this device. Technical deployment success ranges between 88 and 100%. Significant reduction in time to hemostasis allows for earlier patient ambulation and shorter in-hospital stay compared to manual compression with peripheral complications not being increased.

Angioplasty, Balloon, Coronary↗

PubMed1999

Laser angioplasty of restenosed coronary stents: results of a multicenter surveillance trial. The Laser Angioplasty of Restenosed Stents (LARS) Investigators.

OBJECTIVES: This study evaluated safety and efficacy of excimer laser angioplasty for treatment of restenosed or occluded coronary stents. BACKGROUND: Balloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis. METHODS: A total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty. RESULTS: Laser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Adult↗

PubMed1999

Improved high-frequency transthoracic flow velocity measurement in the left anterior descending coronary artery after intravenous peripheral injection of levovist.

New ultrasonic technology allows noninvasive measurement of the flow in the distal left anterior descending coronary artery. The goal of this study was to validate transthoracic determination of coronary flow velocity with the intracoronary Doppler flow wire technique. In 20 patients with normal coronary arteries, 2 intracoronary and 2 comparative transthoracic Doppler measurements (TTDMs) of the average peak velocity (APV) and the mean systolic and diastolic velocities were performed. The diastolic/systolic ratio was calculated. Blood flow velocity was determined in the distal left anterior descending coronary artery with a Doppler guide wire. Color Doppler and subsequent pulsed wave Doppler readings in an optimal left lateral position were available within 1 hour after completion of the invasive examinations. TTDM were performed during continuous administration of 2.0 g of contrast agent. A modified apical view was obtained from the fourth or fifth intercostal space, and a high-frequency transducer was used (7 MHz for 2-dimensional and 6 MHz for color Doppler imaging; 3.5 MHz for pulsed wave Doppler readings). The Doppler flow signal quality was graded from I to III (I = no flow mapping obtainable, II = poor quality, III = Doppler signals with a well-defined outline). In 13 (65%) patients, 26 TTDMs revealed signal quality of grade III. APV was calculated to be within normal limits (APVecho = 19.96 +/- 7.62 cm/s vs APVinvasive = 20.77 +/- 7.87 cm/s). APVecho correlated well with APVinvasive (r = 0.85, y = 0.82x + 2.85, P <.001). The mean difference between APVecho and APVinvasive (Bias) was -0.81 +/- 4.23 cm/s. No correlation was found between invasive and noninvasive measurements of diastolic/systolic velocity ratios (P >.05). High-frequency TTDM provides reliable data on APV in the majority of patients. It has the potential to be introduced as a relevant screening test for follow-up of patients after interventional treatment.

Blood Flow Velocity↗

PubMed1999

Does remodeling occur in the diseased human saphenous vein bypass grafts? An intravascular ultrasound study.

BACKGROUND: Coronary artery remodeling is a common phenomenon in human atherosclerotic arteries. Controversies exist concerning the presence of absence of the remodeling process in diseased human coronary saphenous vein bypass grafts. The purpose of the study was to observe the vessel and lumen dimensions in patients who had undergone saphenous vein grafting with intravascular ultrasound to find out whether the remodeling process exists in the diseased human saphenous vein bypass grafts. METHODS: A total of 43 saphenous vein bypass grafts from 43 patients (39 males, 4 females, mean age 63+/-8 years); 1-16 years (mean 9.3+/-4.0 years) after grafting, who had not undergone previous catheter intervention, were studied using intravascular ultrasound. The vessel, lumen and plaque area were measured at the lesion segment as well as in the proximal and distal reference segments. The percent stenosis was calculated. RESULTS: In 43 bypass grafts having severe stenosis before intervention, plaque was eccentric in 69.4% and concentric in 30.6%. No calcification was detected in 75% cases and 25% cases has mild-moderate intimal calcification. The vessel area in the lesion segment was 19.0+/-9.7 mm2, significantly larger than the proximal reference segment 12.8+/-4.0 min2 as well as the distal reference segment 12.9+/-3.6 mm2 (p < 0.001). It was also larger than that of the average area of the proximal and distal reference segments (p < 0.001). The vessel area increased in accordance with plaque area (p < 0.001). A weak relationship existed between vessel area and percent stenosis (r = 0.37, p = 0.04). CONCLUSION: In contrary to previous findings, diseased human saphenous vein bypass grafts undergo focal compensatory enlargement (remodeling) in the presence of plaque formation. The underlying mechanism is probably similar to that in de novo atherosclerosis.

Adaptation, Physiological↗

PubMed1999

A prognostic computer model to individually predict post-procedural complications in interventional cardiology: the INTERVENT Project.

AIMS: The purpose of this part of the INTERVENT project was (1) to redefine and individually predict post-procedural complications associated with coronary interventions, including alternative/adjunctive techniques to PTCA and (2) to employ the prognostic INTERVENT computer model to clarify the structural relationship between (pre)-procedural risk factors and post-procedural outcome. METHODS AND RESULTS: In a multicentre study, 2500 data items of 455 consecutive patients (mean age: 61.1+/-8.3 years: 33-84 years) undergoing coronary interventions at three university centres were analysed. 80.4% of the patients were male, 16.7% had unstable angina, and 5.1%/10.1% acute/subacute myocardial infarction. There were multiple or multivessel stenoses in 16.0%, vessel bending >90 degrees in 14.5%, irregular vessel contours in 65.0%, moderate calcifications in 20.9%, moderate/severe vessel tortuosity in 53.2% and a diameter stenosis of 90%-99% in 44.4% of cases. The in-lab (out-of-lab) complications were: 0.4% (0.9%) death, 1.8% (0.2%) abrupt vessel closure with myocardial infarction and 5.5% (4.0) haemodynamic disorders. CONCLUSION: Computer algorithms derived from artificial intelligence were able to predict the individual risk of these post-procedural complications with an accuracy of >95% and to explain the structural relationship between risk factors and post-procedural complications. The most important prognostic factors were: heart failure (NYHA class), use of adjunctive/alternative techniques (rotablation, atherectomy, laser), acute coronary ischaemia, pre-existent cardiac medication, stenosis length, stenosis morphology (calcification), gender, age, amount of contrast agent and smoker status. Pre-medication with aspirin or other cardiac medication had a beneficial effect. Techniques, such as laser angioplasty or atherectomy were predictors for post-procedural complications. Single predictors alone were not able to describe the individual outcome completely.

Adult↗