Surgical treatment of evolving and sustained myocardial infarction.
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Coronary Artery Bypass↗
Biomedical subjects
L H Cohn
Publications and source records attributed to L H Cohn.
Surgical treatment of acute myocardial infarction.
Thus, in 1987, the following indications for surgical treatment of acute myocardial infarction are: 1) acute evolving myocardial infarction less than six hours from onset, in patients in whom PTCA or streptokinase, depending on the coronary anatomy, has been unsuccessful; in single vessel disease, CABG is unlikely; in multiple-vessel disease, CABG is preferable to SK/PTCA therapy unless a very major "culprit" lesion can be identified with certainty; 2) post-infarction angina hours to days after a transmural myocardial infarction unyielding to maximal medical therapy and in patients with a coronary artery obstruction not amenable to PTCA; 3) occlusion of a coronary artery during cardiac catheterization that cannot be fixed by PTCA and/or streptokinase; 4) occlusion of a coronary artery during PTCA causing hemodynamic obstruction and threatened myocardium subtended by the obstructed coronary artery; 5) balloon-dependent patients in cardiogenic shock without mechanical defects who have adequate residual left ventricular function as determined by regional wall motion studies; 6) ventricular septal defect secondary to myocardial infarction unless there is terminal organ damage; 7) mitral valve replacement with or without coronary bypass for acute papillary muscle rupture; 8) semi-emergent cardiac transplantation, either with or without a mechanical bridge to transplant in young individuals (less than 50 years) who have suffered massive destruction of left ventricular myocardium by an acute coronary occlusion with or without recurring ventricular tachyarrhythmias. Ejection fraction in this clinical category is always under 0.20 and usually under 0.15.
Angina Pectoris↗
The paradox of high-tech health care. Has our technology outstripped our ability to be ethical, cost effective and timely in its delivery?
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Aged↗
Effects of antegrade cardioplegic infusion with simultaneously controlled coronary sinus occlusion on preservation of regionally ischemic myocardium after acute coronary artery occlusion and reperfusion.
This study was conducted to assess the protective effects of antegrade infusion of cardioplegic solution with simultaneously controlled coronary sinus occlusion on regionally ischemic myocardium after acute coronary occlusion and reperfusion. Twelve sheep were subjected to 1 hour of occlusion of the distal left anterior descending coronary artery. Sheep in group I (n = 6) were subjected only to infusion of potassium crystalloid cardioplegic solution into the aortic root, whereas in group II (n = 6) a stitch was snared around the proximal coronary sinus for its subsequent occlusion during antegrade infusions of cardioplegic solution. All animals were placed on cardiopulmonary bypass. Five hundred milliliters of cardioplegic solution at 4 degrees to 8 degrees C was administered in three divided doses during the total cross-clamp period of 30 minutes. The occlusion of the left anterior descending artery was then released, and the animals were weaned from bypass and studied for an additional 4 hours. Coronary sinus pressure, myocardial temperature, regional function assessed by pairs of ultrasonic crystals, global function assessed by rate of rise of left ventricular pressure and cardiac output, and the area at risk and area of necrosis were determined. The heart was excised at the end of the experiment and stained. Animals treated by the technique of antegrade infusion combined with coronary sinus occlusion had more homogeneous myocardial cooling during cardioplegic infusions and better recovery of the first derivative of left ventricular pressure and regional segment shortening at 90 and 270 minutes of reperfusion than those treated with antegrade infusion alone (p less than 0.01 and p less than 0.05, respectively). The group treated by antegrade infusion of cardioplegic solution combined with coronary sinus occlusion had an area of necrosis/area at risk ratio of 40.5% +/- 1.2%; the antegrade infusion group, 58.3% +/- 4.1% (p less than 0.01). These data suggest that antegrade infusion combined with coronary sinus occlusion may be an improved method of global and regional myocardial protection in the presence of an occluded coronary artery.
Animals↗
The effect of superoxide dismutase and catalase on the extended preservation of the ex vivo heart for transplantation.
The applicability of heart transplantation remains limited in part by the inability to preserve the excised heart for long periods of time. Free radical scavengers have been shown to protect the anoxic myocardium by preventing damage to the cell membrane and may, therefore, be effective in extending successful preservation of donor hearts. We perfused 10 sheep hearts for 8 hours in an ex vivo perfusion system. The effect of superoxide dismutase combined with catalase, 60,000 units/L, was studied in five sheep, and five received placebo. Control determinations and determinations after 8 hours of preservation were obtained with the heart perfused with autologous blood at 37 degrees C at an aortic perfusion pressure of 60 mm Hg and flow of 180 to 200 ml/min. After control readings, the hearts were arrested and perfused with a cold (6 degrees to 8 degrees C) oxygenated buffered crystalloid solution with or without superoxide dismutase and catalase at a perfusion pressure of 30 cm H2O for 8 hours. Left and right ventricular compliance was measured sequentially with separate intraventricular balloons. After 8 hours of ex vivo preservation, hearts receiving superoxide dismutase and catalase had significantly better left and right ventricular performance, higher myocardial oxygen consumption, and lower lactate production than the control group. The hearts preserved with superoxide dismutase and catalase showed significantly better left and right ventricular compliance, much less increase in heart weight, and no change in the diastolic pressures. The results suggest that superoxide dismutase combined with catalase may be effective in extending ex vivo preservation of hearts for cardiac transplantation.
Animals↗
Effects of diltiazem cardioplegia on global function, segmental contractility, and the area of necrosis after acute coronary artery occlusion and surgical reperfusion.
We investigated the effects of diltiazem cardioplegia on myocardial function and infarct size in the region of the left anterior descending artery after acute occlusion and reperfusion during cardiopulmonary bypass. Sheep (30 kg) were subjected to 1 hour of regional myocardial ischemia by occlusion of the left anterior descending artery and assigned to a control (n = 8) or experimental group (n = 5). Control animals were placed on cardiopulmonary bypass and the heart arrested with potassium cardioplegia. The left anterior descending artery was released and two additional doses of 100 ml of cardioplegic solution were infused during the total cross-clamp time of 30 minutes. The animals were then weaned from bypass after 1 hour and beating, working reperfusion maintained for an additional 4 hours. The experimental group followed the same protocol except that the cardioplegic solution contained diltiazem (1.4 mg/L). Segmental myocardial function was determined by pairs of ultrasonic crystals in the area at risk, control segment, and minor axis. Global contractility was determined from maximum derivative of left ventricular pressure and cardiac output. The area at risk was determined by injecting monastral blue dye into the left atrium with the left anterior descending artery briefly reoccluded, and the area of necrosis was determined by measuring with a planimeter non-triphenyltetrazolium chloride stained areas in the sectioned left ventricle. After 5 hours of reperfusion, not only did the diltiazem group demonstrate better global contractility as defined by the derivative of left ventricular pressure (1853 +/- 292 versus 979 +/- 191, p = 0.05) but, in addition, the systolic shortening in the ischemic area improved significantly when compared with the control group (9.4 +/- 4 versus 2.13 +/- 0.77, p = 0.05). The group receiving diltiazem cardioplegia had an area of necrosis to area at risk ratio of 31.4% +/- 3%, which was significantly better than this ratio in the control group of 60.75% +/- 7% (p = 0.01). Diltiazem cardioplegia results in improved global and segmental contractility and limits the infarct size after occlusion of the left anterior descending artery and surgical reperfusion.
Animals↗
The effect of oxygen free radical scavengers on the recovery of regional myocardial function after acute coronary occlusion and surgical reperfusion.
This study investigated the effects of the oxygen free radical scavengers superoxide dismutase and catalase, the peroxide ion inhibitor, in crystalloid potassium cardioplegic solution on infarct size and global and regional myocardial function after occlusion of the left anterior descending artery and surgical reperfusion in young sheep on cardiopulmonary bypass. After 1 hour of occlusion, the animals were randomized to receive either routine potassium cardioplegia or cardioplegia with superoxide dismutase and catalase. Global hemodynamics measured by maximum rate of pressure rise showed significant improvement after 5 hours of reperfusion in the group treated with superoxide dismutase and catalase (1843 +/- 163 versus 979 +/- 191, p less than 0.001). Regional myocardial function was measured by ultrasonic crystals implanted in the ischemic area and in a nonischemic control segment. The percent systolic shortening or bulging was calculated. At end of reperfusion in the animals treated with superoxide dismutase and catalase, there was active shortening in the ischemic area after reperfusion of +9.2% +/- 0.4% versus 2.1% +/- 0.8% in untreated animals (p less than 0.001). Infarct size measured by triphenyltetrazolium chloride staining showed significant difference (p less than 0.001) between animals treated with superoxide dismutase and catalase (0.9% +/- 0.1%) and control animals (61% +/- 70%). Superoxide dismutase and catalase given in the cardioplegic solution before reperfusion of an acutely ischemic area of myocardium enhances recovery of contractile function and results in a significant reduction in infarct size, which suggests improved salvage of the ischemic myocardium.
Animals↗
Hemodynamic and pathologic evaluation of a unileaflet pericardial bioprosthetic valve.
This study investigated the in vivo hemodynamics and pathologic changes of a unileaflet pericardial bioprosthetic valve 3 to 5 months after implantation in juvenile sheep. Group 1 had 10 sheep with tricuspid valve replacement. Group 2 had nine sheep with mitral valve replacement. Group 3 served as a control with 10 sheep that had tricuspid valve replacement with a trileaflet porcine bioprosthesis. Hemodynamic performance was satisfactory in all three groups despite prominent pathologic changes, particularly in unileaflet valves. Intrinsic cuspal calcification was present in 66% of the unileaflet tricuspid, 88% unileaflet mitral, and 25% porcine tricuspid valves. Neither cuspal tearing nor perforations were found. However, cuspal stretching and redundancy of the mobile cusp was present in six tricuspid, seven mitral unileaflet valves, and no porcine valves. Gross pericardial redundancy correlated with the microscopic appearance of distorted and separated collagen bundles. These findings suggest that multiple modes of primary tissue failure may limit the durability of this unileaflet pericardial valve.
Animals↗
Guidelines for reporting morbidity and mortality after cardiac valvular operations.
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Documentation↗
Measurement of coronary blood flow: a critical review.
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Animals↗
Mitral and tricuspid valve repair.
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Bibliographies as Topic↗
Nitrous oxide for blood pressure control after coronary artery surgery: a dose-response hemodynamic study in postoperative patients.
The inhaled anesthetic nitrous oxide is used for sedation in the coronary care unit and has been advocated as an antihypertensive agent in patients after a cardiac operation. To delineate the hemodynamic effects of nitrous oxide after cardiac surgery, we studied 11 patients with a mean age of 63 years who had undergone isolated coronary artery bypass grafting. All patients had major coronary artery disease and normal preoperative hemodynamic function. When patients were in stable condition in the intensive care unit, hemodynamic measurements were made at an inspired oxygen concentration of 40% with progressive doses of nitrous oxide (0, 10, 20, 40, and 60%). Measured and calculated hemodynamic data were compared using analysis of variance. Nitrous oxide caused significant decreases in mean arterial pressure in a dose-related fashion; pressure fell 6 mm Hg at 10% nitrous oxide and 11 mm Hg at 60% nitrous oxide (6 and 13% decreases). These changes were not associated with significant alteration in pulmonary artery pressure or cardiac index. Left ventricular stroke work index decreased significantly with the administration of nitrous oxide. We conclude that, in patients with normal hemodynamic and ventricular function, the administration of nitrous oxide for its sedative and antihypertensive effects is safe in the postoperative period and may be useful, especially in patients who are candidates for early extubation.
Aged↗
Left thoracotomy and femoro-femoral bypass for reoperative revascularization of the posterior coronary circulation.
Left thoracotomy and femoro-femoral cardiopulmonary bypass has been used for reoperation in five patients requiring coronary bypass graft into the inferolateral surface of the heart. Five patients had refractory angina pectoris and angiographic occlusion of lateral wall native vessels or previous occluded vein grafts and all had positive exercise test. Four of the five had patent internal mammary to the LAD. Following supine positioning and removal of the saphenous vein and isolation of the femoral artery and femoral vein, a left fifth interspace thoracotomy was made, the patient heparinized and cannulated for cardiopulmonary bypass, the pericardium opened, the heart dissected free, and either the internal mammary artery dissected off the left chest wall or saphenous vein grafts used to bypass the appropriate lesions. The proximal inflow was the descending thoracic aorta making tunnels for the vein grafts through the posterior pericardium. All of the patients did well in the postoperative period. This technique is recommended for reoperations in patients with documented inferolateral ischemia as the primary cause of symptomatology with mitigating circumstances against an anterior approach.
Adult↗
Time course of resolution of pulmonary hypertension and right ventricular remodeling after orthotopic cardiac transplantation.
Most patients with severe congestive heart failure have secondary pulmonary hypertension (PHT). Elevation of pulmonary vascular resistance (PVR) to greater than 480 dynes.sec.cm-5 (6 Wood units) is currently the principle hemodynamic contraindication to orthotopic cardiac transplantation. We performed serial two-dimensional Doppler echocardiographic examinations and right heart catheterizations in 24 recipients (21 men, 14-58 years old) of orthotopic cardiac transplants to determine the time course of resolution of PHT and the concomitant remodeling of the donor right ventricle. Right and left heart filling pressures declined in parallel and reached the upper normal range at 2 weeks after the transplant procedure and remained unchanged at 1 year follow-up. Mean pulmonary arterial pressure (mm Hg) decreased from 38 +/- 9 preoperatively to 22 +/- 5 at 2 weeks and was 19 +/- 5 at 1 year after the transplantation procedure. At 1 year after surgery, PVR had decreased from 202 +/- 89 dynes.sec.cm-5 preoperatively to 99 +/- 36 dynes.sec.cm-5 (p less than .001), while cardiac output increased from 3.7 +/- 1.2 to 6.3 +/- 1.5 liters/min (p less than .001). Echocardiographic analysis showed that transplant recipients had an enlarged right ventricle on day 1 after surgery, and a volume overload contraction pattern and tricuspid regurgitation was present in the majority. This increase in right ventricular size was maintained at 1 year follow-up while the incidence of tricuspid regurgitation decreased. We conclude that there is rapid resolution of moderately elevated pulmonary arterial pressures after cardiac transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
The effect of amino acid L-glutamate on the extended preservation ex vivo of the heart for transplantation.
The present study was undertaken to assess the effect of L-glutamate on the extended preservation of the heart ex vivo added to a hypothermic preservative solution. Ten sheep hearts were removed after application of cold crystalloid potassium cardioplegia. The hearts were immersed in iced normal saline and right ventricular and left ventricular intraventricular balloons were connected to transducers to measure compliance. Thermistor probes were placed in the interventricular septum. The heart was mounted on a retrograde perfusion apparatus via the cannula in the brachiocephalic trunk and placed in an isolated glass cylinder. The perfusion apparatus consisted of a roller pump, a heat exchanger, and a pediatric membrane oxygenator. Control determinations and those after 8 hr of preservation were made while the hearts were perfused with enriched autologous blood. Right and left ventricular compliance, left ventricular systolic and diastolic pressures, right ventricular systolic and diastolic pressures, left ventricular dP/dt, coronary arteriovenous oxygen consumption, lactate production, and heart weight were measured. Results showed significantly improved left and right ventricular systolic function with L-glutamate preservation. Whole heart oxygen consumption in the L-glutamate group showed a 4% increase, while the placebo group showed a significant decrease in oxygen consumption after 8 hr of preservation. The glutamate-preserved hearts also showed no change in lactate production after 8 hr of preservation as compared with a 81% increase in the placebo group. After 8 hr of perfusion there was 67% increase in the heart weight of the control and a 42% increase in the L-glutamate group.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Early and late results of coronary bypass surgery. Evolution and the influence of cardioplegia.
Comparison of 1085 patients having coronary bypass surgery without cardioplegia from Jan. 1970 to Aug. 8, 1977 with 1060 patients operated upon with cardioplegia from Aug. 9, 1977 to Dec. 31, 1980 suggests that improved myocardial protection afforded by cardioplegia combined with profound topical hypothermia has its principal impact in those patients requiring urgent or emergency operations by reducing the probability of intraoperative left ventricular failure after coronary bypass. The need for postoperative balloon pumping and the risk of intraoperative death were significantly lower in patients operated upon with hypothermia + cardioplegia myocardial protection. In patients who survived 30 days after operation there was no significant improvement in long-term survival, incidence of myocardial infarction, or recurrence of angina pectoris in the cardioplegia group despite a greater average number of grafts per patient and a smaller number of ungrafted but obstructed coronary arteries.
Adult↗
Performance of a fabricated trileaflet porcine bioprosthesis. Midterm follow-up of the Hancock modified-orifice valve.
The fabrication of the Hancock modified-orifice valve raised questions about its long-term durability. Since 1976, 315 patients (206 male, 109 female) with a mean age of 63 years underwent aortic valve replacement with 21 mm (n = 120), 23 mm (n = 153), 25 mm (n = 36), and 27 mm (n = 6) Hancock modified-orifice valves. There were five operative deaths (1.6% mortality). Two hundred sixty-two patients are alive 2 to 117 (mean 53) months postoperatively. Actuarial probability of survival at 96 months was 78% +/- 3%. Two hundred twenty-two survivors are in Functional Class I or II. Forty-three patients have had valve-related complications: thromboembolism in 25 (1.9%/pt-yr), primary valve dysfunction in eight (0.6%/pt-yr), and endocarditis in 11 (0.8%/pt-yr). Twelve patients have required reoperation (0.8%/pt-yr) for primary valve dysfunction (four patients), for endocarditis (five patients), and for perivalvular leak (three patients). At 96 months the actuarial probability of freedom from thromboembolism was 87% +/- 3%, from primary valve dysfunction 97% +/- 2%, and from endocarditis 92% +/- 3%. The probability of freedom from all valve-related complications was 78% +/- 4% and from reoperation 94% +/- 2%. The performance of this prosthesis justifies its continued use for aortic valve replacement.
Adult↗
Effect of total spinal anesthesia on arterial and venous responses to dopamine and dobutamine.
To test whether acute denervation alters the vascular effects of dopamine and dobutamine, we anesthetized 16 greyhounds and placed them on total cardiopulmonary bypass (CPB). Eight dogs received total spinal anesthesia before drug testing; eight dogs were tested in the absence of total spinal anesthesia. During dopamine and dobutamine infusions, venous capacitance [determined by the volume of the CPB venous reservoir (VR)] and mean arterial pressure (MAP) were monitored. The CPB pump flows remained constant throughout our studies. Every dog received six increasing doses of both drugs. In the absence of total spinal anesthesia, both dopamine and dobutamine increased VR (decreased venous capacitance) in a dose-dependent manner. Dobutamine decreased MAP in a dose-related fashion but dopamine had no significant effect on MAP. After total spinal anesthesia, both dopamine and dobutamine produced greater dose-related increases in VR (i.e., decreases in venous capacitance) than in the absence of spinal anesthesia. Dopamine increased MAP but dobutamine had no significant effect. These data demonstrate how dopamine and dobutamine differ in their effects on the arterial circulation in the presence or absence of spinal anesthesia. The acute denervation of spinal anesthesia altered venous and arterial dose-response relationships of both drugs. Finally, our study demonstrates the effectiveness of dobutamine and, perhaps even more so, dopamine as possible alternatives to ephedrine for the pharmacologic correction of the noncardiac circulatory sequelae of spinal anesthesia.
Anesthesia, Spinal↗