Transluminal extraction catheter atherectomy followed by immediate stenting in treatment of saphenous vein grafts.

OBJECTIVES: The purpose of this study was to evaluate the effectiveness of transluminal extraction catheter (TEC) atherectomy followed by immediate Palmaz-Schatz coronary stenting of coronary bypass vein grafts. BACKGROUND: Degeneration of saphenous vein coronary bypass grafts has become a common problem. Repeat bypass surgery is associated with greater risk and a poorer outcome than the initial operation. Moreover, percutaneous interventional procedures in vein grafts have been associated with high procedural complication rates, including distal embolization, and high restenosis rates. TEC atherectomy may reduce distal embolization, and stenting may reduce restenosis rates. METHODS: We evaluated the procedural, hospital and clinical outcomes of TEC atherectomy followed by immediate Palmaz-Schatz coronary stenting of 53 vein grafts in 49 consecutive patients. The strategy was to limit instrumentation to extraction debulking and to stabilizing the site with stent deployment before using balloon dilation for optimal gain in lumen diameter. RESULTS: Results are shown as mean value (95% confidence interval [CI]). The mean graft age was 9.2 years (95% CI 7.9 to 10.5), and 1.0 (95% CI 1 to 1) TEC cutter (2.2 mm [95% CI 2.1 to 2.3]) and 1.7 (95% CI 1.4 to 2.0) Palmaz-Schatz coronary stents/ vein graft were used. The procedural success rate was 98%, with a minimal lumen diameter at baseline of 1.3 mm (95% CI 1.1 to 1.5), increasing to 3.9 mm (95% CI 3.6 to 4.2) (p < 0.05) after the TEC-stent procedure. Procedural complications occurred infrequently: graft perforation in 1 (2%) of 53 patients and distal embolization in 1 (2%) of 53 (same patient). In-hospital complications included non-Q wave myocardial infarction in two patients and death after a successful procedure in three (6%) (n = 1 each: massive bleeding from the catheter site; sepsis; and acute myocardial infarction with asystole in the distribution of the stented vessel). The event-free survival rate to hospital discharge was 90%. Clinical follow-up (13 months [95% CI 11 to 15]) was available for all patients. There were five (11%) revascularization procedures (three bypass grafts and two percutaneous transluminal coronary interventions), four (9%) nonfatal myocardial infarctions and five (11%) deaths, for a cumulative rate of 28% for any adverse outcome occurring in 13 of 46 patients. CONCLUSIONS: TEC atherectomy followed by immediate Palmaz-Schatz coronary stenting of stenoses in old (> 9 years) saphenous vein grafts can be successfully performed, with a low incidence of procedural and hospital complications. Clinical restenosis rates are low and less than those previously reported; however, late morbid cardiac events are still frequent in this high risk group of patients. These observational findings suggest that this technique may improve percutaneous management of vein graft disease, but optimal long-term management strategies remain to be determined.

Severe right heart failure in a patient with Grave's disease.

This brief report presents a patient with isolated right heart failure and two rare underlying causes, hyperthyroidism and dysplastic tricuspid valve. Repair of the tricuspid valve and treatment of the hyperthyroidism were both essential for successful treatment of the right heart failure. Most important, recrudescence of hyperthyroidism in this patient was associated with reappearance of florid right heart failure. This report provides further information about a potential linkage of hyperthyroidism and severe right heart failure.

The effect of vagal stimulation on left ventricular systolic and diastolic performance.

Vagal stimulation (VS) decreases heart rate and alters the loading conditions of the left ventricle (LV). However, its effects on LV performance are not clearly defined. To evaluate the effects of VS on LV performance, 20 anesthetized open-chest dogs were instrumented to measure LV pressure (LVP) and volume. VS resulted in a decrease in the slope of the end-systolic pressure-volume relationship, without pacing and with pacing, after ansae subclaviae resection and after ansae subclaviae resection plus beta-adrenergic blockade. VS did not alter the time constant of isovolumic relaxation (tau) or the LV end-systolic pressure-tau relationship during vena caval occlusion. No change was noticed in the LV chamber stiffness constant without and with pacing. However, a significant increase in the LV filling fraction at one-third and one-half of diastole was observed. We examined the mechanism of this increase by examining the relationship of left atrial pressure (LAP) and LVP. VS increased mean LAP 44% and increased the LAP-LVP gradient 42%. These data suggest that VS exerts a significant negative inotropic effect that is independent of its bradycardiac effect and the level of sympathetic tone. Despite the absence of lusitropic effects of VS, early filling of the LV is augmented most likely as a result of an increase in LAP.

Effects of vasoactive intestinal peptide on myocardial performance.

It is now recognized that stimulation of the vagus releases both acetylcholine (ACh) and vasoactive intestinal peptide (VIP). Whereas ACh depresses cardiac function, recent data indicate that VIP may have a cardiostimulatory effect. Exogenously administered VIP appears to enhance left ventricular (LV) contractile function; however, whether endogenously released VIP alters LV performance is not known. Accordingly, we evaluated the effects of exogenous VIP and endogenously released VIP during vagal stimulation after muscarinic and beta-adrenergic blockade (VS-B) on LV performance using pressure-volume analysis. Eight anesthetized open-chest dogs instrumented to measure LV pressure and volume (conductance catheter) were pretreated with atropine (0.1 mg/kg) and propranolol (1 mg/kg). The cervical vagi were transected. Hemodynamic data were obtained at steady state and during transient vena caval occlusion. Exogenous intravenous VIP (0.05 microgram/kg-1 x min-1) increased HR minimally [2.1 +/- 0.9% increase; P = not significant (NS)] but significantly increased maximum first time derivative of left ventricular pressure (dP/dtmax; 29.4 +/- 19.9% increase; P < 0.05) and the slope of the end-systolic pressure-volume relation (Ees; 3.1 +/- 1.3 to 8.9 +/- 4.2 mmHg/ml; P < 0.05). Minimum first time derivative of left ventricular pressure (dP/dtmin) decreased 22 +/- 16.2% (P < 0.05), and the time constant of isovolumic relaxation (tau) decreased 38 +/- 18% (P < 0.05). During VS-B (20 Hz, 15 v, 5 min), HR increased significantly (98 +/- 11 to 130 +/- 26 beats/min; P < 0.05). Ees also increased significantly (3.3 +/- 1.6 vs. 5.2 +/- 2.8 mmHg/ml; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Radionuclide myocardial perfusion imaging.

Objective assessment of myocardial perfusion is important in the diagnosis, management and long-term follow-up of patients with coronary artery disease. Thallium-201 perfusion imaging provides valuable information about myocardial viability, regional myocardial blood flow and physiologically important coronary artery disease at rest, during exercise and during pharmacologically induced coronary vasodilation. Dipyridamole "stress" myocardial imaging is indicated in the evaluation of patients who are unable to exercise or who cannot achieve 85 percent of the maximum predicted heart rate. It also may be useful in the preoperative assessment of patients undergoing elective vascular surgery.