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Biomedical subjects

P Hanrath

Publications and source records attributed to P Hanrath.

At least 181 records · Page 10Linked to original sources
PubMed1996

Dobutamine stress echocardiography after coronary artery bypass grafting. Transthoracic vs biplane transoesophageal imaging.

Graft failure or progressive native vessel disease can be a serious problem after coronary artery bypass grafting. However, because of poor image quality it may be difficult to evaluate these patients by transthoracic stress echocardiography. The purpose of this study, therefore, was to evaluate the effectiveness of dobutamine stress echocardiography in the detection of myocardial territories with compromised vascular supply (due to either an obstructed native vessel without graft, and obstructed graft, or a native vessel obstructed distal to bypass graft insertion with < or = 50% luminal diameter reduction on angiography) after coronary artery bypass grafting and to determine additional information obtained by biplane transoesophageal stress echocardiography. Sixty patients (54 men, mean age 59 +/- 8.5 years) who had undergone coronary bypass grafting (total number of graft vessels 198) were evaluated from 6 months to 14 years (mean 6.2 years) after surgery. Transthoracic dobutamine stress echocardiography, biplane transoesophageal dobutamine stress echo, and coronary angiography were performed and evaluated by independent examiners. An infusion of dobutamine up to a maximum of 40 micrograms.kg-1.min-1 was administered, and additional atropine (0.25-1.0 mg) was given if 85% of age-predicted maximal heart rate was not reached. Biplane transoesophageal echocardiography was performed in the transgastric short-axis view as well as transoesophageal 4- and 2-chamber views, allowing division of the left ventricle into a 14-segment scheme. Wall motion abnormalities induced with dobutamine stress were used to predict regional vascular insufficiency. A 4-point scale, ranging from 'excellent' (1) to 'impossible' (4) was used to assess each system's ability to evaluate all left ventricular segments. Forty-five patients, of whom 35 were identified by transthoracic echocardiography (sensitivity 78%), had at least one territory with a compromised vascular supply. In 15 patients, the vascular supply was uncompromised, with 13 showing no wall motion abnormalities inducible by transthoracic echocardiography (specificity 86%). However, biplane transoesophageal echocardiography had a higher sensitivity and specificity than transthoracic echocardiography in detecting compromised vascular supply, 93% and 93%, respectively. The former system correctly classified the vascular supplies in 113 of 120 vascular territories (94%), according to whether they were compromised or uncompromised. This was significantly more (P < 0.05) than by classification with transthoracic dobutamine echocardiography, by which system only 102 of the 120 vascular territories were correctly assessed (85%). Compared with the conventional transgastric monoplane short-axis view, examination using three different views via a biplane probe results in a higher sensitivity (93% vs 84%). Assessed on a 4-point scale, the ability to evaluate all left ventricular segments was 2.3 +/- 0.7 (mean +/- SD) for transthoracic echocardiography and 1.7 +/- 0.7 (P < 0.01) for biplane transoesophageal echocardiography. After coronary artery bypass grafting transthoracic dobutamine stress echocardiography has acceptable accuracy in the detection of regional vascular insufficiency. However, this accuracy can be improved using the higher image quality of transoesophageal echocardiography, combined with the advantages of several different views obtained by biplane transoesophageal echocardiography.

Aged↗
PubMed1996

Left ventricular volume calculations using a multiplanar transoesophageal echoprobe; in vitro validation and comparison with biplane angiography.

BACKGROUND: Biplane angiographic and transthoracic echocardiographic volume calculations have shown to be sufficiently reliable in symmetric hearts; however, they are unreliable in the presence of aneurysmatic distortions. Multiplane transoesophageal echocardiography offers unobstructed cross-sectional views of the heart from one stable transducer position with the potential of imaging irregular cavity forms more accurately. It was the purpose of this in vitro study to compare the precision of multiplanar transoesophageal echocardiography to that of biplane angiography in determining left ventricular volumes, especially in aneurysmatic models. METHODS: Seven silicon rubber models of the left ventricle from post-mortem specimens (four with aneurysms) were filled with 30 different volumes (range 153-256 ml, 197 +/- 30 ml). Echocardiographic cross-sections (20 degree rotational steps) were obtained from different transducer positions, utilizing a multiplanar probe with a central rotational axis. Volumes were calculated using the disc-summation method. For comparison the same volumes were determined by standard biplane angiography. The minimum number of echo cross-section necessary to optimize precision was analysed by calculating volumes for each increasing equidistant rotational step. RESULTS: Linear correlation between measured volume using a multiplanar transoesophageal echoprobe and true volume was high (r = 0.97) and significantly better than for biplane angiography (r = 0.88; P < 0.001). Measurement bias and imprecision were also significantly lower with multiplanar echocardiography than with biplane angiography (3.9 +/- 7.1% vs 11.1 +/- 15.4%, and 2.0 +/- 3.7% vs 5.9 +/- 8.3%; P < 0.001). Precision of biplane angiographic volume measurements was significantly influenced by the presence of aneurysmatic distortions. Multiplanar echo volumes, however, were not influenced by left ventricular geometry and transducer positions. Nine echo cross-sections provided optimal precision. CONCLUSIONS: Three-dimensional echocardiographic volume calculations using a multiplanar transoesophageal echoprobe and the disc-summation method provide precise measurements unaffected by left ventricular geometry and transducer position in an in vitro setting. Standard biplane angiography is significantly less precise.

Angiography↗
PubMed1996

Intracoronary Doppler flow velocity measurements in two patients with solitary coronary ostium: is there true obstruction?

BACKGROUND: Coronary anomalies in the absence of other major cardiac malformations are rare, with an incidence of less than 1-1.5%. Although most have been incidental findings without clinical relevance, a subgroup of anomalies has been identified that are associated with cardiac symptoms or even sudden cardiac death. This subgroup includes an ectopic origin and abnormal course of the left coronary artery from the right sinus of Valsalva. RESULTS: We examined two patients with this anomaly. In patient I the left main coronary artery took a deep intramural course anterior to the pulmonary trunk, and in patient II the left anterior descending coronary artery took its course between the pulmonary trunk and ascending aorta. Both anomalies were identified by coronary angiography and that in patient I was confirmed by surgery. Intracoronary Doppler flow velocity measurements during cardiac catheterization, including atrial pacing in patient II, demonstrated significant flow acceleration in both patients. This occurred within the intramural segment (in patient I) and in the segment between the pulmonary artery and ascending aorta (in patient II). CONCLUSIONS: These findings indicate that external vessel compression is one pathophysiological mechanism that leads to ischaemia and a longstanding history of cardiac symptoms in these patients. Invasive haemodynamic measurements such as these have not previously been available.

Blood Flow Velocity↗
PubMed1996

Detection of abnormal aortic elastic properties in asymptomatic patients with Marfan syndrome by combined transoesophageal echocardiography and acoustic quantification.

OBJECTIVE: To evaluate the potential value of transoesophageal echocardiography combined with automated border detection and acoustic quantification for the assessment of elastic properties of the thoracic aorta in patients with Marfan syndrome. SUBJECTS: 16 patients with Marfan syndrome and 12 age matched normal controls. METHODS: Transoesophageal echocardiography was performed in all subjects. Minimum and maximum diameters of the descending thoracic aorta were obtained from M mode images and acoustic quantification was used for the on-line evaluation of cross sectional aortic area and peak positive area changes over time. Compliance, distensibility, and stiffness index were calculated using M mode data and non-invasively measured blood pressure and were compared with the indices derived from acoustic quantification. RESULTS: Aortic dimensions normalised for body surface area were not statistically different between patients and normal controls, but there were significant differences for all elasticity indices except compliance. Marfan patients had a lower distensibility [4.2 (SD 1.8) v 5.8 (2.1) cm2/dyn, P < 0.05] and a higher stiffness index [9.7 (3.0) v 7.1 (1.8), P < 0.05]. The dynamic indices derived from the acoustic quantification were significantly smaller in Marfan patients [peak positive area change: 5.1 (1.0) v 7.7 (1.7) cm2/s; P < 0.001; and normalised peak positive area change: 2.5 (1.2) v 4.0 (0.8) cm2/s respectively, P < 0.001] and were suitable to discriminate between normal and abnormal elastic properties. CONCLUSIONS: In Marfan syndrome elastic properties of the descending aorta are significantly different from normal controls, even in the absence of vessel dilatation. In addition to established static indices, indices derived from acoustic quantification reflect dynamic changes of the cross sectional area for the evaluation of regional vessel mechanics. The on-line assessment of peak positive area change allows differentiation from normal individuals and may be more accurate than standard M mode measurements.

Adult↗
PubMed1996

[Dobutamine stress echocardiography and perfusion scintigraphy for detection of myocardial ischemia in patients with and without previous myocardial infarct].

UNLABELLED: Dobutamine stress echocardiography has proven to be a method with high diagnostic accuracy in the detection of coronary artery disease. In case of previous myocardial infarction it is of importance to detect additional regions with inducible myocardial ischemia. This study aimed at the detection of inducible ischemia by dobutamine stress echocardiography and stress perfusion scintigraphy in patients without and with previous myocardial infarction. 50 patients without as well as 50 patients with previous transmural myocardial infarction were investigated. In all patients coronary angiography, technetium-99m methoxy-isobutyl-isonitrile (MIBI)-SPECT after bicycle ergometry and dobutamine stress echocardiography (up to 40 mcg/kg/min dobutamine, 1 mg atropine) were performed within 14 days. In patients with previous myocardial infarction dobutamine stress echocardiography and MIBI-SPECT had similar sensitivities (91 vs. 94%, n.s.) and specificities (81 vs. 75%; n.s.) in the detection of significant coronary artery disease. Agreement on the presence or absence of inducible ischemia was 84% (Kappa = 0.60). In patients with previous transmural myocardial infarction sensitivity of stress echocardiography and perfusion scintigraphy in the detection of significant coronary artery disease is lower with 63% and 77%, respectively. In this patient group transient perfusion defects were found more frequently than inducible wall motion abnormalities, 76% and 60%, respectively. There was a lower agreement (76%; Kappa = 0.49) in the detection of abnormal or normal results between dobutamine echocardiography and stress perfusion scintigraphy for this group of patients. CONCLUSION: This study demonstrates high agreement of dobutamine stress echocardiography and stress perfusion scintigraphy in the evaluation of inducible ischemia in patients without previous transmural myocardial infarction and equal diagnostic accuracy in the detection of coronary artery disease. In patients with previous myocardial infarction there is a lower agreement in the interpretation of patients as having ischemia due to negative dobutamine echo results in patients having positive perfusion scintigraphies.

Adult↗
PubMed1996

[Comparison of NYHA classification with cardiopulmonary function in patients with chronic heart failure].

In this study a correlation was sought between the NYHA class, the results of cardiopulmonary exercise testing (CPX) and the ejection fraction (EF) measured by echocardiography and scintigraphy. Of 36 patients enrolled, CHF in 20 patients was due to CAD and in 16 patients due to DCM. The NYHA class was determined independently by two cardiologists who were blinded to the CPX, echocardiography or scintigraphy results. Sixteen patients were classified as class II and 20 as class III. As a control, 23 patients without cardiopulmonary disease were examined. The CPX was done according to a ramp protocol with continuous measurement of respiratory gases, maximal oxygen consumption (VO2-max) and oxygen consumption at the anaerobic threshold (VO2-AT). A correlation (p = 0.0425) between the NYHA classification and the Weber classification for VO2-AT was found. There was no correlation for VO2-max. VO2-AT was significantly higher in NYHA II patients as compared to NYHA III patients. No significant difference was seen in relation to the VO2-max. In comparison to the normal group, the VO2-AT and VO2-max were significantly lower in NYHA II and III patients. There was no significant correlation between VO2-AT and EF, VO2-max and EF, or between NYHA class and EF. During a 16-month follow-up period lethality was 8/14 patients with VO2-AT < 10 ml/kg/min. Although the NYHA classification provides a valid method for determining the prognosis of CHF patients, if feasible, the CPX examinations should be used to provide updates of the disease progress.

Adult↗
PubMed1996

[Assessment of myocardial viability using 201TL SPECT at rest to predict the reversibility of left ventricular wall motion abnormalities].

AIM: The aim of the present study was to predict preoperatively the reversibility of left ventricular wall motion abnormalities using TI-201 SPECT at rest. METHODS: 19 patients with advanced coronary artery disease and regional wall motion abnormalities were examined at rest with TI 201 SPECT (acquisition 15 minutes and 3 hours post injection). Successfully revascularized, proven by a second coronary angiography three month after revascularisation. Wall motion was again evaluated by cineventriculography. RESULTS: The preoperative a- or dyskinetic segments were best separated by the minimal relative TI-201 uptake in the defect 3 hrs p.i. in (i) postinterventionally improved wall motion (TI-201 uptake 67 +/- 14%, viable) and in (ii) without recovery (TI-201 uptake 46 +/- 12%, p < 0.001, non viable). A threshold at a TI-201 uptake of more than 50% yielded a positive predictive value of 0.73 and a negative predictive value of 0.86. If the segments with wall motion abnormalities (hypokinetic included) were evaluated as one group, no such threshold was obtained all segments which occurred a TI-201 uptake of more than 80% showed a functional recovery, wall motion did not improve in any segment with a TI-201 uptake of less than 40%. In the present study a considerable influence of the defect localisation with regard to the posterior wall was not observed. The values of TI-201 redistribution under resting condition were not useful to predict functional recovery. CONCLUSION: TI-201 SPECT in rest predicts preoperatively the reversibility in regions with severe wall motion abnormalities only and indicates myocardial viability in these cases. Thus, the method is basically useful to determine myocardial viability. In hypokinetic segments, however, a wide range of TL-201 uptake values exists without definite evidence to functional recovery.

Aged↗
PubMed1996

[Effect of myocardial viability and coronary revascularization on clinical outcome and prognosis: a follow-up study of 161 patients with coronary heart disease].

One hundred and sixty-one consecutive patients (144 male, 57 +/- 9 years) with stable coronary artery disease underwent nuclear imaging for assessment of myocardial viability using Tc-99m sestamibi single-photon emission computed tomography (SPECT) and F-18 fluoro-deoxy-glucose (FDG) positron emission tomography (PET). 88% had a history of chronic myocardial infarction and all had angiographically proven regional wall motion (RWM) abnormalities in the distribution territory of a stenosed or occluded coronary artery. Patients were followed for 29 +/- 6 (22-44) months with 84/161 patients (52%) receiving elective revascularization by either bypass surgery or angioplasty. 61/84 patients underwent follow-up angiography after 5 +/- 2 months for quantitative assessment of RWM changes using serial analysis with the centerline method in 45 pts with technically suitable paired angiograms. Myocardial regions were classified according to semiquantitative analysis of regional sestamibi and FDG uptake as either normal, regions with evidence for maintained viability but no mismatch ("mild match"), regions with a perfusion/metabolism "mismatch," or scar. RWM improved in "mismatch" regions from -2.2 +/- 1.0 SD to -1.0 +/- 1.4 SD (p < 0.01) compared to the mean of a normal reference population. In contrast, in regions with a "mild match" or those classified as scar, RWM analysis revealed no functional changes at follow-up. For the assessment of clinical outcome, patients were divided into three groups depending on the result of viability imaging. Those with predominantly scar tissue in the target region for viability assessment (group A, n = 90), those with a "mild match" (B, n = 26), and group C (n = 45) consisting of patients with a "mismatch" pattern. Subsequent treatment was not blinded to nuclear imaging results and revascularization was performed in 30% of group A (group A2), 81% of group B, and 80% of group C, while the other patients were treated medically only. Cardiac events during follow-up were defined as cardiac death, myocardial infarction, unstable angina with subsequent revascularization, cardiac transplantation, and survived resuscitation without evidence for myocardial infarction. Group C demonstrated a significant reduction of cardiac events from 22% to 0% following revascularization, whereas in group A coronary revascularization did not influence the frequency of events. Subjective assessment of angina pectoris and heart failure symptoms revealed more patients with improvement following revascularization as compared to those treated medically. Thus, combined nuclear imaging using sestamibi SPECT and FDG PET with quantitative tracer uptake analysis allows detection of absent or preserved myocardial viability in regions with reduced perfusion and function with prognostic implication for regional myocardial functional outcome as well as for identification of patients who benefit most from coronary revascularization.

Adult↗
PubMed1995

Age-related changes in the elastic properties of the aortic tree in normotensive patients: investigation by intravascular ultrasound.

The arterial wall structure degenerates with increasing age, elastin fibers decrease while collagen increases. We investigated the elastic properties of the aorta and iliac arteries to determine the relationship between aging and arterial mechanics. The regional elasticity of the aorta and iliac arteries was determined at five different sites in 40 normotensive patients aged 32 to 78 years. A combined procedure for arterial blood pressure measurement and arterial cross-sectional area determination was employed to calculate the parameters of compliance and pulse wave velocity. The descending thoracic and abdominal aorta showed significant correlations between age and elasticity. No correlation was observed at the aortic bifurcation. A significant correlation between age and pulse wave velocity was apparent in the common iliac artery, whereas compliance showed no significant correlation to age. In the external iliac artery as well, no significant correlation between age and elasticity could be found. Arterial elasticity decreases with age, but this process does not progress uniformly at all sites of the arterial system. The difference in elasticity between these basic types of arteries diminishes throughout life. At the aortic bifurcation, mechanical aging seems to proceed faster than at unbifurcated arterial segments.

Adult↗
PubMed1995

Long-term clinical and echocardiographic follow-up after surgical correction of hypertrophic obstructive cardiomyopathy with extended myectomy and reconstruction of the subvalvular mitral apparatus.

BACKGROUND: The standard surgical approach to hypertrophic obstructive cardiomyopathy (HOCM) was modified in the present series with a combination of extended myectomy with partial excision and mobilization of the papillary muscles. METHODS AND RESULTS: Between 1979 and 1992, 58 patients (38 men and 20 women; mean age, 49 +/- 24 years) with HOCM were operated on with the use of this different technique. Their intraventricular gradients were 79 +/- 33 (+/- SD) mm Hg at rest and increased to 147 +/- 48 mm Hg with provocative maneuvers. Mild-to-moderate mitral regurgitation was present in 60% of the patients, and severe regurgitation was present in 5%. Ten patients required additional aortocoronary bypass graft surgery. Follow-up (mean, 84 months) was complete (100%). Hemodynamic improvement was documented by a significant (P < .01) decrease in left ventricular end-diastolic pressure from 19 +/- 9 to 14 +/- 6 mm Hg and reduction of basal outflow tract gradients to 5 +/- 7 mm Hg at rest and 16 +/- 24 mm Hg after provocation. Late mortality was 1.4% per patient-year, and no sudden cardiac deaths occurred during follow-up. Functional status was excellent for 84% of the patients; 8 patients were in New York Heart Association functional class III, and none were in class IV. Echocardiography revealed no outflow tract obstruction. CONCLUSIONS: Extended myectomy and reconstruction of the subvalvular mitral apparatus in HOCM result in excellent functional improvement with relief of outflow tract obstruction. The technique can be performed safely despite its more aggressive surgical nature and allows an individualized strategy depending on the patient's extent and distribution of left ventricular hypertrophy.

Adolescent↗
PubMed1995

Incremental value of biplane and multiplane transesophageal echocardiography for the assessment of active infective endocarditis.

In 41 patients with clinical evidence of active infective endocarditis, transesophageal echocardiography was performed in a stepwise manner, starting with evaluation of the monoplane views, followed by the longitudinal plane, and finally by the intermediate planes. Number, location, length, area, density, extent, and mobility of vegetations and abscesses were assessed in the monoplane, biplane, and best intermediate planes to identify and quantify the incremental value of the longitudinal and intermediate planes. Eighty-three vegetations and 6 abscesses were found. In 4 patients (10%) monoplane evaluation yielded false-negative results. There were no false-negative results using the biplane evaluation. However, when compared with multiplane evaluation, additional vegetations were missed in 23% of patients after monoplane and in 9% of patients after biplane evaluation. Three abscesses were missed using the monoplane and 1 was missed using the biplane technique. The area was underestimated in 60% of all vegetations (mean underestimation, 37% +/- 23% [SD] of maximal area) and length in 49% of cases (mean underestimation, 38% +/- 23% [SD] of maximal length) of all vegetations when biplane was compared with multiplane evaluation. Also, with monoplane and biplane evaluation, mobility and density were misinterpreted in 6% and 5% and 17% and 9% of all vegetations, respectively. Thus, multiplane transesophageal echocardiography is more accurate than the monoplane and biplane techniques in assessing patients with active infective endocarditis.

Abscess↗
PubMed1995

The ryanodine binding sarcoplasmic reticulum calcium release channel in nonfailing and in failing human myocardium.

The ryanodine-sensitive Ca2+ release channel (RyaCRC) of the sarcoplasmic reticulum plays a key role in the intracellular Ca2+ handling in cardiomyocytes. Altered expression of the RyaCRC has been supposed to contribute to abnormal cellular Ca2+ handling and to myocardial dysfunction in dilated and ischemic cardiomyopathy. In the present study the 3H-ryanodine binding site in human myocardial homogenates was characterized and the density of the RyaCRC (which corresponds to the cardiac ryanodine receptor) was determined in nonfailing and in failing human myocardium. Homogenates were prepared from nonfailing left ventricular myocardium from the hearts of 5 organ donors (NF) and from failing myocardium from 14 explanted hearts of transplant recipients with end-stage heart failure resulting from dilated (DCM, n = 5) or ischemic (ICM, n = 9) cardiomyopathy. Radioligand saturation binding experiments revealed a specific, high-affinity 3H-ryanodine binding site (Kd-values: NF: 0.65 +/- 0.11 nmol/l, DCM: 0.66 +/- 0.09 nmol/l, ICM: 0.88 +/- 0.18 nmol/l; n.s.) in all preparations. Specific 3H-ryanodine binding depended on the free Ca2+ concentration in the assay. It was maximal at 3-100 micro mol/l Ca2+. The binding was inhibited by the RyaCRC antagonists ruthenium red (Ki-value: 0.32 [0.18-0.56] micromol/l, n = 5) and Mg2+ (Ki-value: 2.95 [1.23-7.11] mmol/l, n = 5). The RyaCRC density was 103.5 +/- 11.9 fmol/mg protein in nonfailing myocardium. There was no significant change in the RyaCRC density in dilated or ischemic cardiomyopathy (112.4 +/- 17.1 and 122.7 +/- 13.9 fmol/mg protein) compared to nonfailing control myocardium. In summary, 3H-ryanodine binds specifically and with high-affinity to the RyaCRC in human myocardium. There is no change in the RyaCRC density in failing myocardium of patients with DCM or ICM in comparison to non-failing controls.

Adult↗
PubMed1995

Effect of captopril on myocardial beta-adrenoceptor density and Gi alpha-proteins in patients with mild to moderate heart failure due to dilated cardiomyopathy.

In end-stage heart failure due to idiopathic dilated cardiomyopathy beta 1-adrenoceptors are downregulated and Gi alpha-proteins are upregulated. The aim of the present study was to investigate the influence of the angiotensin-converting enzyme inhibitor captopril on beta-adrenoceptor density and Gi alpha-proteins in sequential endomyocardial biopsies. Nineteen patients with mild to moderate congestive heart failure due to idiopathic dilated cardiomyopathy (NYHA Class II-III) were studied before and after 8-11 weeks of therapy. Patients were randomised into a captopril and a control group; 9 patients received captopril 12.5-50 mg per day, (divided in 2-3 doses) p.o. in addition to "conventional" therapy with digoxin and diuretics, and 10 controls received "conventional" therapy only. Echocardiography, spiroergometry, right heart catheterisation and endomyocardial biopsies were performed before (baseline) and after treatment. Compared to baseline, captopril increased total beta-adrenoceptor density by selectively increasing beta 1-adrenoceptors (31.6 vs 41.2 fmol.mg-1; p < 0.05) but had no significant effect on Gi alpha-proteins. The results indicate that treatment with angiotensin-converting enzyme inhibitors partly restores myocardial beta 1-adrenoceptor density, and this action effect may contribute to the clinical improvement of patients with idiopathic dilated cardiomyopathy treated in this way.

Adenosine Diphosphate Ribose↗
PubMed1995

Effects of blood pressure reduction on the elastic profile of the aortic tree in patients with coronary heart disease.

Decreased arterial compliance of large arteries in coronary heart disease has been reported. Using intravascular ultrasound it was demonstrated that arterial compliance decreases with increasing distance from the heart. Until now changes in the elastic profile have not been investigated after a stepwise blood pressure (BP) reduction induced by antihypertensive agents. The local viscoelastic properties of the aortic tree were analyzed before and after a mean arterial BP reduction of about 5 and 15 mm Hg below baseline by the steady-state infusion of increasing doses of nisoldipine in 15 patients with coronary artery disease. Intravascular ultrasound imaging combined with arterial pressure measurements were performed at five sites along the aortic tree to determine the viscoelastic profile before nisoldipine administration and again after the 5 and 15 mm Hg nisoldipine-induced blood pressure reductions. The elasticity parameters varied depending on the distance from the heart and on the BP level. At both BP reduction levels nisoldipine infusion led to an increase in arterial compliance at the abdominal aorta and at the aortic bifurcation. A dissociation between the 5 and the 15 mm Hg BP reduction was found at the common iliac artery and at the external iliac artery. Our results provide direct quantitative evidence that stepwise BP reductions exhibit different and, in part, contrary effects on the elastic profile, depending on the aortic tree location. The results also suggest that nisoldipine infusion can significantly ameliorate local viscoelastic properties at the abdominal aorta and at the aortic bifurcation, an effect that was associated or caused by a change in BP attributable to a decrease in peripheral resistance.

Adult↗
PubMed1995

Functional assessment of PTCA results by stress echocardiography: when and how to test.

Angiographic follow-up has shown that restenosis after PTCA is a continuous and ubiquitous process rather than a dichotomous event. Since the functional significance of restenosis involves more factors than minimal lumen diameter, functional tests after PTCA cannot be expected to match exactly the degree of angiographic restenosis. In the past, nuclear perfusion imaging has been the most accurate non-invasive method to predict restenosis, but now there is a new technique: stress echo. This uses physical (treadmill, exercise), pharmacological (dipyridamole, dobutamine), or pacing stress (together with transoesophageal imaging) for the detection of stress-inducible wall motion abnormalities; resolution of resting abnormalities may also be observed. These stress modalities have been employed to detect restenosis in limited numbers of patients, with diagnostic accuracies (so far, except for dobutamine) comparable to nuclear imaging. Therefore, it seems that the decision to use echo stress testing depends on patient characteristics, availability of methods, and, importantly, experience of the echo laboratory. Timing of the test after PTCA must take into account delayed functional recovery after PTCA; this has been well described by nuclear perfusion imaging. Thus, very early (< 1 month) tests lack specificity. On the other hand, development of restenosis after 6 months is rare. Stress tests therefore should be performed within the time window of 1 to 6 months after PTCA.

Angioplasty, Balloon, Coronary↗