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Biomedical subjects

J Matloff

Publications and source records attributed to J Matloff.

At least 37 records · Page 2Linked to original sources
PubMed1985

A 6 year experience with the St. Jude medical valve: hemodynamic performance, surgical results, biocompatibility and follow-up.

After in vitro testing (confirmed in vivo) of three contemporary valve designs (St. Jude, Björk-Shiley and Carpentier-Edwards) demonstrated that the St. Jude valve possessed the most favorable hydrodynamic performance characteristics, a limited clinical trial was begun in high risk patients who might benefit from a prosthesis with improved hemodynamics. Between March 1978 and March 1984, 419 St. Jude prostheses (157 aortic, 156 mitral and 53 double aortic-mitral) were implanted in 366 patients. Ninety-six percent were in New York Heart Association functional class III or IV preoperatively. Early (30 day) mortality was 10.4% overall, and was lower after aortic (5.7%) or double (7.5%) than after isolated mitral valve replacement (16.0%). Forty-four prosthetic mitral valve recipients with severe ischemic mitral regurgitation experienced a 32% early mortality rate; without this group, mitral valve replacement carried a 10% early mortality rate (p less than 0.01). Multivariate logistic regression analysis confirmed that early death was strongly associated with three preoperative patient characteristics (p less than 0.05): ischemic mitral valve disease, depressed left ventricular function (ejection fraction less than 0.55) and advanced functional class (class IV). Late follow-up (7,055 patient-months, mean 22) was 99.7% complete (1 patient lost). Actuarial survival at 4 years was 80, 80 and 79% after aortic, mitral (nonischemic) and double valve replacement, respectively; in the subset with ischemic mitral regurgitation, actuarial survival was 34% (p less than 0.01). Eighty-six percent of survivors were in functional class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)

Biocompatible Materials↗
PubMed1985

Delineation of peripheral and coronary detail by intraoperative angioscopy.

In this study, the development of intraoperative angioscopy, the value of the information obtained, and the problems encountered with the procedure are reported. Eight angioscopes, 1.5 to 2.8 mm in diameter, with a line resolution of greater than 0.4 mm at 5 mm, were used. One-hundred ten angioscopic investigations were performed in 46 patients; 24 at peripheral bypass surgery and 22 at coronary artery bypass surgery. These included 68 arteries, 28 new anastomoses, six old grafts, five laser angioplasties, and three in situ vein grafts. The most important finding was that angioscopic data provide information not available from probes or angiography. Angioscopic findings were responsible for a change in surgical procedures in 12 patients (26%) including three anastomotic revisions, three alterations in graft site placement, and two repeat thrombectomies. The most significant technical problems were lack of steerability and insufficient irrigation, which resulted in poor angiographic images. Further technical development is necessary before routine intraoperative angioscopy is practical. Nevertheless, if these problems are resolved, angioscopy will provide unique, high-resolution information which can directly alter surgical therapy.

Angioplasty, Balloon↗
PubMed1983

Transient hemodynamic dysfunction after myocardial revascularization. Temperature dependence.

We studied hemodynamics and the effects of right atrial pacing (110 beats/min) following complete myocardial revascularization and hypothermic multidose potassium crystalloid cardioplegia in 12 patients with a normal preoperative left ventricular ejection fraction (LVEF). Measurements were made immediately preoperatively, postoperatively at specified temperatures during the rewarming period (90 degrees F, 94 degrees F, and 98 degrees F), and at 24 hours. No patient had a perioperative myocardial infarction. At 90 degrees F, hemodynamics were characterized by significant decreases in cardiac index, stroke volume index, and left ventricular stroke work index (LVSW) and an increase in systemic vascular resistance index (SVRI) compared to preoperative values (p less than 0.05). Right atrial pacing significantly increased cardiac index preoperatively and 24 hours postoperatively, but not during the rewarming period. Over the entire rewarming period (90 degrees F to 98 degrees F), each of the following variables correlated with temperature: cardiac index (r = 0.71 in sinus rhythm and r = 0.66 with right atrial pacing); stroke volume index (r = 0.33 and 0.66); SVRI (r = -0.80 and -0.64); LVSW (r = 0.37 and 0.73); and heart rate in sinus rhythm (r = 0.51). During the rewarming period, there was an inverse relationship between cardiac index and SVRI (r = -0.87). In conclusion, after myocardial revascularization: (1) transient hemodynamic dysfunction occurs during the rewarming period (90 degrees F to 98 degrees F); (2) this dysfunction is temperature-dependent; and (3) right atrial pacing at 110 beats/min does not improve hemodynamic function during the rewarming period. Temperature must be considered in the evaluation of left ventricular and hemodynamic function following myocardial revascularization.

Adult↗
PubMed1982

Preoperative prediction of reversible myocardial asynergy by postexercise radionuclide ventriculography.

Myocardial asynergy is sometimes reversed by coronary bypass, and a noninvasive method of predicting which assess are reversible would be desirable. To assess whether changes in myocardial wall motion observed immediately after exercise can differentiate reversible from nonreversible myocardial asynergy, we evaluated 53 patients by radionuclide ventriculography before and after exercise and again at rest after coronary bypass surgery. Preoperative improvement in wall motion immediately after exercise was highly predictive of the surgical outcome (average chance-corrected agreement, 91 per cent). At surgery the asynergic segments that had improved after exercise were free of grossly apparent epicardial scarring. The accuracy of these predictions for postoperative improvement was significantly greater (P less than 0.01) than that of analysis of Q waves on resting electrocardiography (average chance-corrected agreement, 40 per cent). In contrast, preoperative changes in left ventricular ejection fraction after exercise were not predictive of postoperative resting ejection fraction. We conclude that postexercise radionuclide ventriculography can be used to identify reversible resting myocardial asynergy. This test should prove effective in predicting which patients with myocardial asynergy are most likely to benefit from aortocoronary revascularization.

Adult↗
PubMed1982

Effects of digoxin on myocardial oxygen supply and demand in patients following coronary artery bypass surgery.

Although digoxin is used frequently in patients in the prophylaxis of postoperative supraventricular tachyarrhythmias, the effects of the drug on myocardial oxygen supply and demand after coronary bypass have not been described. Seven adult patients with good ventricular function who underwent myocardial revascularization were studied before and three hours after digoxin (0.5 mg, iv). There were no significant changes observed in any measured systemic hemodynamic variable. Evaluation of global myocardial metabolism showed an increase in myocardial oxygen consumption (P less than 0.05) which was compensated satisfactorily, as no significant alteration was noted in the coronary sinus oxygen content, or in the lactate gradient across the myocardium. Since the authors studied the effects of only one dose of digoxin, the effects of full digitalization in these patients remains to be defined.

Aged↗
PubMed1982

Right atrial tamponade complicating cardiac operation: clinical, hemodynamic, and scintigraphic correlates.

Persistent bleeding into the pericardial space in the early hours after cardiac operation not uncommonly results in cardiac tamponade. Single chamber tamponade also might be expected, since in this setting the pericardium frequently contains firm blood clots localized to the area of active bleeding. However, this complication has received very little attention in the surgical literature. We are therefore providing documentation that isolated right atrial tamponade can occur as a complication of cardiac operation and that there exists a potential for misdiagnosis and hence incorrect treatment of this condition. Right atrial tamponade may be recognized by a combination of low cardiac output, low blood pressure, prominent neck veins, right atrial pressure in excess of pulmonary capillary wedge pressure and right ventricular end-diastolic pressure, and a poor response to plasma volume expansion. Findings on chest roentgenogram and gated wall motion scintigraphy may be highly suggestive. This review should serve to increase awareness of this complication and to provide some helpful diagnostic clues.

Bioprosthesis↗
PubMed1981

Use of thallium-201 redistribution scintigraphy in the preoperative differentiation of reversible and nonreversible myocardial asynergy.

Thallium-201 (201Tl) redistribution scintigraphy might differentiate reversibly from nonreversibly asynergic myocardial segments and thus predict the response of these segments to coronary artery bypass grafting (CABG). To test this hypothesis, 25 consecutive patients undergoing CABG, preoperative stress-redistribution 201Tl scintigraphy, and both pre- and postoperative resting equilibrium radionuclide ventriculography were evaluated. For both types of scintigraphic study, each patient was imaged in the same three views. Because of the effects of CABG on septal motion, this region was considered separately. Postoperative improvement was noted in 54% of 72 preoperative asynergic segments. Improvement was common not only in hypokinetic but also in akinetic and dyskinetic segments, and occurred in a similar proportion of studies performed early (less than 2 weeks) or late (3-6 months) after CABG. Thallium-201 redistribution scintigraphy was highly predictive of the pattern of postoperative asynergy: The redistribution pattern was normal in 90% of segments with reversible asynergy and abnormal in 76% of segments with nonreversible asynergy. The presence or absence of pathologic Q waves was less sensitive in this differentiation. Septal segments, however, frequently demonstrated abnormal wall motion postoperatively, despite normal 201Tl redistribution scintigraphy. Resting left ventricular ejection fraction (LVEF) was generally unchanged postoperatively, but in some patients with multiple areas of reversible asynergy it did improve. Thus, 201Tl redistribution scintigraphy appears to reliably distinguish viable from nonviable asynergic myocardial zones, and predicts the response of these segments to CABG.

Coronary Artery Bypass↗
PubMed1975

Changes in vascular ionic content and distribution across aortic coarctation in the dog.

Eight dogs were subjected to 80-90 percent coarctation of thoracic aorta, which produced a mean blood pressure gradient of 40 mmHg; six normal dogs were used as controls. Proximal aorta was compared with distal aorta, and carotid and femoral arteries removed after coarctation were compared against the contralateral vessels removed before coarctation. After 4 wk of coarctation, proximal aorta contained more total and intracellular Na (derived from 24Na fluxes and space measurements), more Mg, Cl, hydrolyzable SO4 equals to, and H2O than distal aorta. Hydrolyzable SO4 equals to was also higher in proximal than in distal noncoarcted aorta. Carotid arteries removed after coarctation had higher total and "noninulin" Na, higher Ca, and similar hydrolyzable SO4equals to and total hexosamine than the contralateral normal vessels. Aortic coarctation had no effect on ionic composition of femoral arteries. The data suggest that an increase in intravascular pressure has direct effects on vascular ionic composition. Although ionic changes may vary in different vessels, increased intracellular Na seems to be the most consistent finding.

Animals↗