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Biomedical subjects

M K Hong

Publications and source records attributed to M K Hong.

At least 73 records · Page 4Linked to original sources
PubMed1999

Comparison of cilostazol versus ticlopidine therapy after stent implantation.

The aim of this study was to evaluate the efficacy of cilostazol for prevention of stent thrombosis compared with ticlopidine. Cilostazol is a potent antiplatelet agent with less serious side effects. However, few data are available about the effect of cilostazol in preventing stent thrombosis after coronary stent implantation. Four hundred ninety patients selected for elective stent placement were randomized to receive aspirin plus ticlopidine (n = 243) or aspirin plus cilostazol (n = 247) for 1 month. Clinical and laboratory evaluations were performed at regular interval. There were no differences in baseline characteristics between the 2 groups. During the first 30 days after stent implantation, major cardiac events or adverse drug effects were similar between the 2 groups: ticlopidine (2.9%) vs cilostazol (1.6%) group, p = NS; stent thrombosis (0.4% vs 0.8%, p = NS, respectively), myocardial infarction (0.4% vs 0.8%, p = NS), severe leukopenia (1.2% vs 0%, p = NS), severe thrombocytopenia (0.4% vs 0%, p = NS), and cerebral hemorrhage (0.4% vs 0%, p = NS). Adverse effects led to drug withdrawal in 7 patients in the ticlopidine group (2.9%) and in 5 in the cilostazol group (2.0%). There was no death during the follow-up period. Thus, aspirin plus cilostazol may be an effective antithrombotic regimen with comparable results to aspirin plus ticlopidine after elective coronary stenting.

Adult↗
PubMed1999

Improvement in exercise capacity and exercise blood pressure response after transcoronary alcohol ablation therapy of septal hypertrophy in hypertrophic cardiomyopathy.

Transcoronary alcohol ablation (TAA) therapy of septal hypertrophy was recently proposed as a therapeutic modality for obstructive hypertrophic cardiomyopathy (HC). However, questions remain about the effect of TAA on exercise performance. We performed a time-course analysis of exercise capacity and exercise hemodynamics in 20 patients with symptomatic obstructive HC after TAA. Symptom-limited bicycle exercise testing was performed before and 3 and 12 months after TAA, and cardiac catheterization at 3-month follow-up. The pressure gradient of the left ventricular outflow tract immediately decreased from 58 +/- 8 to 4 +/- 1 mm Hg at rest (p <0.01) and from 143 +/- 11 to 30 +/- 6 mm Hg after extrasystole (p <0.01), but partially recovered at 3-month follow-up (14 +/- 4 and 40 +/- 9 mm Hg, respectively). Left ventricular end-diastolic pressure was not changed after TAA. Peak oxygen consumption increased from 19 +/- 2 to 23 +/- 1 ml/kg/min (p < 0.01) and exercise duration from 573 +/- 47 to 742 +/- 46 seconds (p <0.01) at 3-month follow-up, but thereafter reached a plateau. Abnormal patterns of exercise blood pressure response were shown in 9 patients but normalized after TAA. Major complications occurred in 4 patients: no reflow to the left anterior descending coronary artery in 2 patients and ventricular tachycardia requiring cardioversion in 2 patients. During the follow-up period, all patients survived with symptomatic improvement in 17 patients. Thus, TAA is a promising therapeutic modality with improvement in exercise capacity and abnormal exercise blood pressure response in obstructive HC. However, potential serious complications should be considered in the application of TAA.

Adult↗
PubMed1999

Immediate results and late clinical outcomes after new CrossFlex coronary stent implantation.

This study evaluates the safety and efficacy of the new CrossFlex stent in the treatment of native coronary artery disease. The CrossFlex stent is a flexible, balloon-expandable new device with an excellent flexibility, radial strength, conformability, and radio-opacity. Little data are available concerning the clinical and angiographic outcomes of this device. The CrossFlex stent was implanted in 209 consecutive patients with 226 lesions. Follow-up angiography was performed at 6 months, and clinical evaluation was undertaken at regular intervals after stent implantation. Procedural success was achieved in all lesions without in-hospital complications. Angiographic follow-up data were available in 153 of the 187 eligible lesions (follow-up rate, 82%), and the overall angiographic restenosis rate was 16.3%. Minimal lumen diameter immediately after stent placement was the only predictor of angiographic restenosis. Clinical follow-up was obtained in all patients at 10.5 +/- 5.2 months. There were 4 deaths (1 cardiac in origin, the others noncardiac in origin), and 1 nonfatal myocardial infarction (nonstented artery) during follow-up. Target lesion revascularization was required in 15 patients (7%), and the overall event-free survival rate (death, myocardial infarction, and repeat revascularization) was 87% at the end of the follow-up period. The CrossFlex stent is a safe and effective device with a high procedural success rate, and a favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials are needed to compare the CrossFlex stent with standard slotted-tube stents.

Aged↗
PubMed1999

Intravascular ultrasound predictors of target lesion revascularization after stenting of protected left main coronary artery stenoses.

We evaluated the predictors of late clinical outcomes after stenting of protected left main coronary artery (LMCA) stenoses. Intravascular ultrasound (IVUS) guided stenting of protected LMCA stenoses was performed in 87 consecutive patients between January 1994 and December 1996. Results were evaluated using conventional (clinical, angiographic, and IVUS) methodology. Late (12 month) clinical follow-up information was obtained in all patients. Initial procedural success was achieved in 86 patients (99%). There was 1 in-hospital death (in the 1 patient with a procedural failure). There were no other in-hospital complications, including Q-wave myocardial infarction, emergency bypass surgery, or repeat coronary angioplasty. The overall target lesion revascularization (TLR) rate was 13%. Using multivariate logistic regression analysis, the only independent predictor of TLR was the postintervention lumen area by IVUS. A final lumen area > or =7.0 mm2 was obtained in 74 patients (86%); the TLR rate for these patients was 7%. This was compared with patients with a final lumen area <7.0 mm2 in whom the TLR rate was 50% (p = 0.0011). Stenting of protected LMCA stenoses is safe and effective with acceptable long-term clinical outcomes. The most important factor determining long-term success was the postintervention lumen area by IVUS.

Aged↗
PubMed1999

Predictors of diffuse-type in-stent restenosis after coronary stent implantation.

Diffuse-type in-stent restenosis (ISR) is associated with higher rate of restenosis after balloon angioplasty, requiring new therapeutic modalities; therefore, it is clinically important to identify the determinants of diffuse-type ISR. We evaluate the clinical and angiographic variables to predict diffuse-type ISR after coronary stent placement. Two hundred and ten ISR lesions in 196 patients (diffuse ISR, 114 lesions; focal ISR, 96 lesions) were reviewed in this study. Clinical, procedural and quantitative coronary angiographic parameters were analyzed. Diffuse-type ISR was defined as a > or = 50% lumen narrowing and > or = 10-mm length. Univariate analysis revealed that initial lesion length, smaller vessel size, diabetes, multivessel disease, multiple stents, and long stent were significantly associated with diffuse-type ISR. However, diabetes was the only independent predictor of diffuse-type ISR by stepwise multiple regression analysis (OR, 3.3; 95% CI, 1.4-7.4, P = 0.001). Diabetes was associated with diffuse-type ISR after coronary stent placement. It may reflect enhanced rate of neointimal hyperplasia within the stent in diabetic patients.

Angioplasty, Balloon, Coronary↗
PubMed1999

Prospective randomized trial of corticosteroids for the prevention of restenosis after intracoronary stent implantation.

BACKGROUND: Inflammatory responses have been implicated as one of the major contributors to neointimal hyperplasia after coronary stenting. The aim of this study was to evaluate the effect of pretreatment with single-dose intravenous methylprednisolone on preventing in-stent restenosis. METHODS: One hundred and forty consecutive patients for elective coronary stenting (focal, de novo lesion and reference diameter >/=3 mm) were randomly assigned to either a methylprednisolone or a placebo group. Either 1 g methylprednisolone or placebo was intravenously infused 6 to 12 hours before stenting with one of two types of stents. Follow-up angiography was performed at 6 months and clinical evaluation made at regular intervals. RESULTS: Baseline characteristics were similar between both groups. Stenting was successful in all patients, and in-hospital events did not occur in any patients. Follow-up angiography was performed in 127 patients (follow-up rate of 91.4%). The minimal lumen diameter increased from 0.86 +/- 0.50 mm before intervention to 3.34 +/- 0.42 mm after intervention (P =.02). At follow-up, minimal lumen diameter decreased to 2.14 +/- 0.78 mm (P <. 01). Angiographic restenosis rate was 17.5% in the steroid group and 18.8% in the placebo group (P =.85), with no differences between the 2 types of stent. Clinical follow-up was available in all patients (10.3 +/- 2.5 months) and clinical events during the follow-up period were similar in both groups. CONCLUSIONS: Single-dose pretreatment with intravenous methylprednisolone before coronary stenting had no effect on the change in minimal lumen diameter at a mean follow-up time.

Aged↗
PubMed1999

Procedural results and late clinical outcomes following multivessel coronary stenting.

OBJECTIVES: To evaluate in-hospital and long-term clinical outcomes in a large consecutive series of patients undergoing percutaneous multivessel stent intervention. BACKGROUND: High restenosis and recurrent angina rates have limited the clinical outcomes of multivessel coronary angioplasty before stents were available to improve angioplasty results. METHODS: We evaluated in-hospital and long-term clinical outcomes (death, Q-wave myocardial infarction [MI], and repeat revascularization rates at one year) in 398 consecutive patients treated with coronary stents in two (94% of patients) or three native arteries, compared to 1,941 patients undergoing stenting procedure in a single coronary artery between January 1, 1994 and August 29, 1997. RESULTS: Overall procedural success was obtained in 96% of patients with two- or three-vessel stenting and in 970% of patients with single-vessel stent intervention (p = 0.36). Procedural complications were also similar (3.8% for multivessel versus 2.9% for single vessel, p = 0.14). During follow up, target lesion revascularization was 15% in multivessel and 16% in single-vessel interventions (p = 0.38), and repeat revascularization (calculated per treated patient) was also similar for both groups (20% vs. 21%, p = 0.73). There was no difference in death (1.4% vs. 0.7%, p = 0.26), and Q-wave MI (1.2% vs. 0%, p = 0.02) was lower following multivessel interventions. Overall cardiac event-free survival was similar for both groups (p = 0.52). CONCLUSIONS: Unlike previous conventional angioplasty experiences, multivessel stenting has (1) similar in-hospital procedural success and major complication rates and (2) similar long-term (one year) clinical outcomes compared with single-vessel stenting. Thus, stents may be a viable therapeutic strategy in carefully selected patients with multivessel coronary disease.

Angioplasty, Balloon, Coronary↗
PubMed1999

Cerebral metabolic abnormalities in congestive heart failure detected by proton magnetic resonance spectroscopy.

OBJECTIVES: Using proton magnetic resonance spectroscopy, we investigated cerebral metabolism and its determinants in congestive heart failure (CHF), and the effects of cardiac transplantation on these measurements. BACKGROUND: Few data are available about cerebral metabolism in CHF. METHODS: Fifty patients with CHF (ejection fraction < or = 35%) and 20 healthy volunteers were included for this study. Of the patients, 10 patients underwent heart transplantation. All subjects performed symptom-limited bicycle exercise test. Proton magnetic resonance spectroscopy (1H MRS) was obtained from localized regions (8 to 10 ml) of occipital gray matter (OGM) and parietal white matter (PWM). Absolute levels of the metabolites (N-acetylaspartate, creatine, choline, myo-inositol) were calculated. RESULTS: In PWM only creatine level was significantly lower in CHF than in control subjects, but in OGM all four metabolite levels were decreased in CHF. The creatine level was independently correlated with half-recovery time and duration of heart failure symptoms in PWM (r = -0.56, p < 0.05), and with peak oxygen consumption and serum sodium concentration in OGM (r = 0.58, p < 0.05). Cerebral metabolic abnormalities were improved after successful cardiac transplantation. CONCLUSIONS: This study shows that cerebral metabolism is abnormally deranged in advanced CHF and it may serve as a potential marker of the disease severity.

Adult↗
PubMed1999

Granulomatous 'foreign body reactions' contribute to exaggerated in-stent restenosis.

BACKGROUND: Results of previous studies with stents coated with 'biocompatible' polymers showed that severe inflammatory reaction and subsequent in-stent restenosis may occur. OBJECTIVE: To evaluate the contribution of granulomatous reaction from uncoated stents to formation of in-stent neointimal hyperplasia. METHODS: Uncoated stainless-steel stents were implanted into 21 porcine coronary arteries without oversizing and harvested after 2 months (n = 6) or 6 months (n = 7). We compared the stents with granulomatous reaction with those without foreign-body reaction. RESULTS: Granulomatous reactions occurred in five 21 stents and resulted in there being significantly greater in-stent neointimal hyperplasia than there was with stents without foreign-body reaction (angiographic diameter stenosis 45 +/- 36 versus 16 +/- 16%, area of neointimal 3.30 +/- 1.4 versus 1.22 +/- 0.4 mm2, thickness of neointima 0.46 +/- 0.29 versus 0.11 +/- 0.09 mm, stenosed area 56 +/- 24 versus 20 +/- 7%, P < 0.01 for each comparison). This increase in amount of neointima was accompanied by significantly greater proliferating cell nuclear antibody staining (15 +/- 5 versus 3 +/- 2%, P < 0.05) in the presence of a granuloma near the stent struts. CONCLUSIONS: A localized granulomatous reaction is associated with a significant increase in amount of stent neointima and proliferation of cells. Thus, permanent stent implants may provoke granulomatous vascular reactions that may affect late-healing responses and clinical outcomes.

Animals↗
PubMed1999

Saline infusion via local drug delivery catheters is associated with increased neointimal hyperplasia in a porcine coronary in-stent restenosis model.

BACKGROUND: Catheter-based local drug delivery at the site of stent implantation has been proposed to reduce in-stent restenosis. We examined whether local delivery itself may cause additional vessel wall injury and negate the potential benefit of local drug delivery in a porcine coronary in-stent restenosis model. METHODS: Pigs were randomly assigned to no local delivery (controls, n = 10) or local saline infusion (5 ml) using commercially available catheters (n = 39; Dispatch catheter, Microporous Infusion catheter, and InfusaSleeve) prior to oversized (stent:artery ratio 1.2) coronary stent implantation. The amount of in-stent neointima was evaluated 4 weeks later with angiography and histology. RESULTS: There was no difference in vessel size or stent: artery ratio. However, at follow-up the local saline delivery group had significantly greater diameter stenosis (50 +/- 19% versus 25 +/- 17% in the controls, P < 0.01). Histology revealed similar injury scores but significantly greater neointimal area in the local saline group (3.61 +/- 1.11 mm2 versus 1.96 +/- 0.82 mm2 in the controls, P < 0.01). In a multivariate linear regression analysis, the use of the local delivery catheter was the only independent variable which was positively correlated with the amount of neointima (P = 0.0001). CONCLUSIONS: In this in-stent restenosis model, catheter-based local saline delivery was associated with significantly increased neointimal hyperplasia. Thus, for local drug delivery to reduce in-stent restenosis, the antiproliferative agent should be potent enough to compensate for the additional neointimal hyperplasia from the infusion itself.

Animals↗
PubMed1999

Studies on the histogenesis of myxomatous tissue of human coronary lesions.

Myxomatous tissue is a characteristic component of human coronary artery lesions, found more often in restenotic lesions. It represents a bulky accumulation of stellate-shaped cells of unknown histogenesis that are embedded in a loose stroma. We analyzed 64 atherectomy specimens containing substantial amounts of myxomatous tissue by using immunohistochemistry, in situ hybridization, and electron microscopy techniques. Stellate cells represented a heterogeneous population, sharing features of smooth muscle cells (SMCs), macrophages, as well as antigen-presenting dendritic cells. Like quiescent medial SMCs, the stellate cells in all specimens expressed high levels of SM alpha-actin message and protein and showed heterogeneity with respect to heavy-chain myosin, SM22, desmin, and vimentin. Ultrastructurally, stellate cells resembled SMCs, with some peculiarities that distinguish them from both differentiated and dedifferentiated SMCs. In contrast to quiescent SMCs, the stellate cells expressed high levels of acidic fibroblast growth factor mRNA and protein similar to cells of monocyte/macrophage lineage. However, stellate cells did not express the marker of mature macrophages, HAM56, and were heterogeneous with respect to CD68. Moreover, unlike SMCs, the stellate cells bore some of the major phenotypic markers of dendritic cells: they were S100-positive and showed various reactivity with respect to CD1a and human leukocyte antigen (HLA)-DR. Invasion of myxomatous tissue with CD45RO-positive T lymphocytes was correlated with strong expression of CD1a in these specimens. Stellate cells also expressed a pericyte marker, high-molecular-weight melanoma-associated antigen. We conclude that stellate cells of myxomatous tissue represent a specific phenotype of mesenchymal cells (possibly pericytes), which is activated to express some markers of antigen-presenting cells. These findings suggest involvement of the stellate cells in a local immune response.

Actins↗
PubMed1999

Electromechanical characterization of acute experimental myocardial infarction.

OBJECTIVE: A new cardiac mapping system combines harmless magnetic field energy and tip-deflecting catheters (equipped with location sensors) to obtain real-time 3-dimensional electromechanical maps of the left ventricle endocardial surface without using x-ray fluoroscopy. This experimental study assessed electromechanical changes during acute coronary occlusion and reperfusion in a canine model. METHODS: Group 1 (n = 10) underwent coronary occlusion for 45 minutes followed by reperfusion (n = 6) and group 2 (n = 11) underwent coronary occlusion for 90 minutes. Endocardial peak-to-peak voltage amplitudes and local endocardial shortening values were measured in ischemic and non-ischemic zones at baseline, following coronary occlusion and reperfusion. RESULTS: In ischemic zones, local shortening was significantly reduced during coronary occlusion compared to baseline (Group 1: 4.7 +/- 2.0% at 45 minutes vs. 15.5 +/- 3.4%, p < 0.001, 6.2 +/- 2.1% at 90 minutes vs. 15.5 +/- 3.4%, p < 0.001; Group 2: 5.0 +/- 2.9% at 90 minutes vs. 13.9 +/- 3.3%, p = 0.007). Coronary occlusion caused a significant reduction in voltage potentials in the ischemic area (unipolar voltage at 45 minutes: 32.2 +/- 7.3 mV vs. 36.2 +/- 8.5 mV at baseline, p = 0.03; unipolar voltage at 90 minutes: 30.5 +/- 11.3 mV vs. 38.3 +/- 14.2 mV, p = 0.003; bipolar voltage at 45 minutes: 7.6 +/- 5.5 mV vs. 10.1 +/- 6.0 mV, p < 0.04; bipolar voltage at 90 minutes: 7.6 +/- 4.4 mV vs. 9.8 +/- 6.2 mV, p < 0.02). Voltage amplitudes were no longer reduced during reperfusion (unipolar voltage: 34.3 +/- 10.5 mV vs. 36.2 +/- 8.5 mV, p = 0.26; bipolar voltage: 9.1 +/- 4.5 mV vs. 10.1 +/- 6.0 mV at baseline, p = 0.37), or in non-ischemic regions during either coronary occlusion or reperfusion. CONCLUSIONS: Electromechanical mapping study provides unique insights into acute myocardial infarction and stunning by detection and localization of early electromechanical changes during coronary occlusion and/or reperfusion.

Animals↗
PubMed1998

Diagnosis of coronary vasospasm in patients with clinical presentation of unstable angina pectoris using ergonovine echocardiography.

Although coronary vasospasm can contribute to the development of unstable angina, the definite diagnostic method has not been established. The purpose of this study was to determine if ergonovine echocardiography (detection of regional wall motion abnormality during bedside ergonovine challenge) after angiographic confirmation of insignificant fixed disease would be useful and safe in detecting coronary vasospasm in patients with unstable angina. After control of chest pain with medications in patients admitted to the coronary care unit under the tentative diagnosis of unstable angina, diagnostic coronary angiography was performed. All patients with normal or insignificant fixed disease underwent ergonovine echocardiography after discontinuation of medications for 4+/-1 days. Among 208 consecutive patients enrolled for this study, 75% (156 of 208) showed significant fixed disease in the angiography. Ergonovine echocardiography was performed in 52 patients with insignificant disease, and coronary vasospasm was documented in 33 (63%, 33 of 52). No serious procedure-related arrhythmia or myocardial infarction occurred. Esophageal motility disorder and hypertrophic cardiomyopathy were diagnosed in 6 and 3 patients, respectively. Chest pain of undetermined etiology was the final diagnosis at discharge in 10 patients (5%, 10 of 208); among them chest pain redeveloped in 2 patients, and repeated ergonovine echocardiography revealed positive results. Our data suggest that among patients with the clinical presentation of unstable angina, coronary vasospasm is the main cause of myocardial ischemia in a considerable number of patients with a normal or near-normal angiogram, and ergonovine echocardiography after confirmation of absence of significant fixed disease is useful and safe for noninvasive diagnosis of coronary vasospasm in this setting.

Adult↗
PubMed1998

Procedural results and long-term clinical outcomes following coronary stenting in perimyocardial infarction syndromes.

Initial experiences with coronary stents in acute coronary syndromes have suggested higher risk of ischemic complications and stent thrombosis. We evaluated in-hospital and 1-year clinical outcomes of coronary stent implantation in perimyocardial infarction (MI) syndromes. We studied 334 consecutive patients undergoing stent interventions in the first week after acute MI. Stenting was performed within 24 hours (n = 31), within 1 to 3 days (n = 95), and within 4 to 7 days (n = 208). Stents were used to improve angioplasty results and to treat dissections and abrupt/threatened closure. Postprocedure anticoagulation regimens were aspirin, ticlopidine, and low molecular weight heparin. Overall procedural success was achieved in 93% of patients. Major in-hospital complications included death (1.0%), recurrent Q-wave MI (0.6%), and emergent bypass surgery (3.0%). Stent thrombosis occurred in 0.6% of patients. At follow-up, cardiac event-free survival was 80%, mortality 2.2%, recurrent MI 3.5%, and target lesion revascularization 11%. We conclude that coronary stenting in periinfarction syndromes was effective in achieving sustained clinical benefit up to 1 year with low morbidity and mortality. Thus, stents seem to be a viable therapeutic strategy in patients sustaining perimyocardial infarction syndromes.

Aged↗
PubMed1998

Comparison between left ventricular electromechanical mapping and radionuclide perfusion imaging for detection of myocardial viability.

BACKGROUND: A novel 3-dimensional left ventricular (LV) mapping system uses low-intensity magnetic field energy to determine the location of sensor-tipped electrode catheters within the LV. Using this system, we sought to distinguish between infarcted, ischemic, and normal myocardium by comparing LV electromechanical mapping data with myocardial perfusion imaging studies. METHODS AND RESULTS: Unipolar voltage potentials and local endocardial shortening (LS) were measured in 18 patients (mean age, 58+/-12 years) with symptomatic chronic angina having reversible and/or fixed myocardial perfusion defects on single photon emission computed tomography imaging studies using 201Tl at rest and 99mTc-sestamibi after adenosine stress. Overall, a significant difference in voltage potentials and LS values was found between groups (P<0.001 for each comparison by ANOVA). The average voltage potentials (14.0+/-2.0 mV) and LS values (12.5+/-2.8%) were highest when measured in myocardial segments (n=56) with normal perfusion and lowest (7.5+/-3.4 mV and 3.4+/-3.4%) when measured in myocardial segments with fixed perfusion defects (n=20) (P<0.0001). Myocardial segments with reversible perfusion defects (n=66) had intermediate voltage amplitudes (12.0+/-2.8 mV, P=0.048 versus normal and P=0.005 versus fixed segments) and LS values (10.3+/-3.7%, P=0.067 versus normal and P=0.001 versus fixed segments). CONCLUSIONS: In patients with myocardial ischemia, LV mapping, compared with myocardial perfusion imaging, shows (1) mild reduction of endocardial voltage potentials and LS in segments with reversible perfusion defects and (2) profound electromechanical impairment in segments with fixed perfusion defects. Thus, such an LV mapping procedure may allow the detection on-line of myocardial viability in the catheterization laboratory.

Aged↗
PubMed1998

Preliminary animal and clinical experiences using an electromechanical endocardial mapping procedure to distinguish infarcted from healthy myocardium.

BACKGROUND: A catheter-based left ventricular (LV) endocardial mapping procedure using electromagnetic field energy for positioning of the catheter tip was designed to acquire simultaneous measurements of endocardial voltage potentials and myocardial contractility. We investigated such a mapping system to distinguish between infarcted and normal myocardium in an animal infarction model and in patients with coronary artery disease. METHODS AND RESULTS: Measurements of LV endocardial unipolar (UP) and bipolar (BP) voltages and local endocardial shortening were derived from dogs at baseline (n=12), at 24 hours (n=6), and at 3 weeks (n=6) after occlusion of the left anterior descending coronary artery. Also, 12 patients with prior myocardial infarction (MI) and 12 control patients underwent the LV endocardial mapping study for assessment of electromechanical function in infarcted versus healthy myocardial regions. In the canine model, a significant decrease in voltage potentials was noted in the MI zone at 24 hours (UP, 42. 8+/-9.6 to 29.1+/-12.2 mV, P=0.007; BP, 11.6+/-2.3 to 4.9+/-1.2 mV, P<0.0001) and at 3 weeks (UP, 41.0+/-8.9 to 13.9+/-3.9 mV, P<0.0001; BP, 11.2+/-2.8 to 2.4+/-0.4 mV, P<0.0001). No change in voltage was noted in zones remote from MI. In patients with prior MI, the average voltage was 7.2+/-2.7 mV (UP)/1.4+/-0.7 mV (BP) in MI regions, 17.8+/-4.6 mV (UP)/4.5+/-1.1 mV (BP) in healthy zones remote from MI, and 19.7+/-4.4 mV (UP)/5.8+/-1.0 mV (BP) in control patients without prior MI (P<0.001 for MI values versus remote zones or control patients). In the canine model and patients, local endocardial shortening was significantly impaired in MI zones compared with controls. CONCLUSIONS: These preliminary data suggest that infarcted myocardium could be accurately diagnosed and distinguished from healthy myocardium by a reduction in both electrical voltage and mechanical activity. Such a diagnostic electromechanical mapping study might be clinically useful for accurate assessment of myocardial function and viability.

Animals↗
PubMed1998

Intravascular ultrasound findings in stenting of unprotected left main coronary artery stenosis.

We evaluated the role of intravascular ultrasound (IVUS) in 16 patients with unprotected left main coronary artery (LMCA) stenting compared with 80 patients with other (non-LMCA) native coronary artery stenting and found that (1) additional high-pressure or larger size balloon dilations were more frequently performed in LMCA stenting than in non-LMCA stenting (p <0.05) and (2) after IVUS-guided stent implantation, minimum lumen area was > or = 9 mm2 in 88% of patients who underwent LMCA stenting and in 19% of those who underwent non-LMCA stenting (p <0.001). IVUS guidance may be a more important adjunctive imaging modality in the stenting of unprotected LMCA stenoses than in stenting of non-LMCA stenoses.

Aged↗