Phentolamine and dobutamine.
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Cardiac Surgical Procedures↗
Biomedical subjects
L H Cohn
Publications and source records attributed to L H Cohn.
Disadvantages of prostacyclin infusion during cardiopulmonary bypass: a double-blind study of 50 patients having coronary revascularization.
Prostacyclin (PGI2) has been suggested for use in cardiopulmonary bypass (CPB) because of its positive effects on platelet number and function. Fifty patients who underwent coronary artery bypass grafting using a bubble oxygenator received heparin, 3 mg per kilogram of body weight, and then were randomly assigned to receive PGI2, 25 ng/kg/min, beginning 5 minutes before and until the end of CPB (26 patients) or a placebo (24 patients). Both groups were similar in sex, age, heparin dose, protamine dose, and CPB time. During CPB, mean arterial pressure fell significantly with PGI2 (76 +/- 2 mm Hg to 53 +/- 2 mm Hg; p less than 0.05) and necessitated pressor substances. Platelet counts fell significantly in both groups with the start of CPB, but after 60 minutes were similar in both groups (118 +/- 9 X 10(3) versus 130 +/- 8 X 10(3); not significant [NS]) and were unchanged 3 hours after CPB. Total chest tube output was 647 +/- 51 ml (placebo group) versus 576 +/- 34 ml (PGI2 group) (NS); 18 of the patients given PGI2 required 26 transfusions compared with 16 transfusions in 8 of the patients given a placebo (p less than 0.05). In PGI2 patients, arterial oxygen tension on 100% oxygen fell from 281 +/- 18 mm Hg before CPB to 223 +/- 17 mm Hg immediately after CPB (p less than 0.05). The placebo patients did not show a change in this variable.(ABSTRACT TRUNCATED AT 250 WORDS)
6-Ketoprostaglandin F1 alpha↗
Efficacy and safety of timolol for prevention of supraventricular tachyarrhythmias after coronary artery bypass surgery.
Forty-one patients undergoing coronary artery bypass grafting were randomly assigned to receive prophylactic timolol or placebo, given in a double-blind fashion. beta-Adrenoceptor-blocking therapy was stopped at least one half-life before surgery. Three to 7 hr after surgery (304 +/- 56 min), 0.5 mg of timolol or placebo was given intravenously twice daily in a double-blind manner. When oral medications were resumed postoperatively, 10 mg of timolol twice daily or placebo was continued orally. Continuous electrocardiograms were recorded for 24 hr before and for 7 days after surgery with a standard cassette recorder. No patient received digoxin. Both groups were comparable for frequency of preoperative supraventricular arrhythmias, left ventricular ejection fraction, duration of cardiopulmonary bypass, aortic cross-clamp time, number of bypass grafts, and total duration of monitoring. Analysis of arrhythmias was done by hand counts, and supraventricular arrhythmias were divided into supraventricular tachycardia and atrial fibrillation and/or flutter. Timolol decreased the frequency of supraventricular tachycardia (581 episodes placebo vs 84 timolol; p less than .05) and of atrial fibrillation and/or flutter (291 episodes placebo vs five timolol; p less than .05). Timolol decreased the number of patients with severe (heart rate greater than 200 beats/min, duration greater than 50 beats) episodes of supraventricular tachycardia (four placebo vs 0 timolol; p less than .05) and also decreased the number of episodes of severe (heart rate greater than 200 beats/min, duration greater than 5 min) atrial fibrillation and/or flutter (16 placebo vs one timolol; p less than .005). There were differences in the durations of supraventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)
Atrial Fibrillation↗
The long-term results of aortic valve replacement.
Reliable aortic valve replacement was one of the most significant advances in the treatment of cardiac disease in this century. It allowed, for the first time, a reliable and reproducible method to palliate the symptoms of aortic stenosis and regurgitation and significantly improved longterm survival over that after medical treatment. Sporadic attempts at aortic valve replacement had been conducted in the late 1950s, but the pioneering work of Harken et al, followed by the final development of a reliable device by Starr, Edwards, and coworkers, opened the era of successful aortic valve replacement. We review the prognosis of patients following aortic valve replacement with aortic stenosis and regurgitation with and without associated procedures and evaluate the various types of bioprosthetic and prosthetic valves in current use, presenting advantages and disadvantages of each type of replacement device.
Aortic Valve↗
Aortic and mitral insufficiency complicating fulminant systemic lupus erythematosus.
The cardiac complications of systemic lupus erythematosus (SLE) include a multitude of valvular, myocardial, and pericardial abnormalities resulting from acute and chronic inflammation involving the endocardium, myocardium, and/or pericardium. A case of acute, severe, aortic, and mitral insufficiency occurring as discrete complications of consecutive flares of SLE in the same patient is described with particular emphasis on the clinical and gross pathologic findings. The cardiac complications of SLE, both from a pathologic and clinical standpoint, are reviewed in the context of the uniqueness of this case.
Adolescent↗
Early and late risk of aortic valve replacement. A 12 year concomitant comparison of the porcine bioprosthetic and tilting disc prosthetic aortic valves.
Aortic valve replacement was performed in 912 consecutive patients from January, 1972, to January, 1983. The 616 male and 296 female patients, whose ages ranged from 16 to 95 years (mean 60.6 years and median 63 years), received 663 bioprosthetic valves and 249 tilting disc valves. A higher incidence of Functional Class IV heart disease and ascending aortic aneurysms was noted in the group receiving the tilting disc valve. Six hundred fifty-seven patients had primarily aortic stenosis and 255 had primarily aortic regurgitation. Associated procedures were done in 308 patients (33%): 233 had coronary bypass grafting, 46 had replacement of ascending aortic aneurysms, and 29 had miscellaneous procedures. The overall operative mortality was 6.4% (59/912). The operative mortality was 4.5% (29/640) for isolated aortic valve replacement, 4.2% (21/233) for valve replacement plus coronary bypass, and 17% (8/46) for valve replacement plus replacement of an ascending aortic aneurysm. The mortality was 4.2% (20/663) for the group receiving bioprostheses and 12.4% (31/249) for those receiving tilting disc valves. The operative mortality for 1983 for all aortic valve replacement procedures was 2.1%; for isolated valve replacement, 1%; for valve replacement plus coronary bypass, 4.4%; and for valve replacement plus aortic aneurysm replacement, 0%. The long-term follow-up was analyzed as of Jan. 1, 1984, so that there was a minimum follow-up of 12 months (mean 55 months and median 51 months). The actuarial survival rate at 108 months for all patients was 67% +/- 2%; for valve replacement alone, 71% +/- 3%; for valve replacement plus coronary bypass, 58% +/- 7%; for valve replacement plus ascending aortic aneurysm replacement, 45% +/- 10%; for aortic stenosis, 70% +/- 3%; for aortic regurgitation, 61% +/- 4%; for Functional Classes I to III, 77% +/- 3%; for Class IV, 53% +/- 4%; for age less than 63 years, 75% +/- 3%; and for age greater than 63 years, 57% +/- 4%. At 108 months, the probability of freedom from thromboembolism was 85% +/- 3% after bioprosthetic valve replacement and 83% +/- 3% after replacement with a tilting disc valve (p = NS). The probability of freedom from hemorrhage at 108 months was 98.6% +/- 7% for the bioprosthetic valve group and 89% +/- 2% for the tilting disc valve group (p less than 0.001). The valve thrombosis rate was 0.34% per patient-year for the tilting disc valves and 0.07% per patient-year for the bioprostheses.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
Effects of reperfusion after acute coronary occlusion on the beating, working heart compared to the arrested heart treated locally and globally with cardioplegia.
To determine whether acutely ischemic myocardium could be more effectively salvaged by reperfusion on cardiopulmonary bypass (CPB) in the cardioplegia-treated heart than with reperfusion in the beating, working heart, 52 greyhound dogs underwent 3 hours of left anterior descending (LAD) occlusion and were randomly assigned to one of four groups. In Group I (19 dogs) the LAD occlusion was released at 3 hours and reperfusion continued in the beating, working heart for an additional 3 hours. Group II (six dogs), Group III (14 dogs), and Group IV (13 dogs) were placed on CPB and underwent 45 minutes of hypothermic ischemic arrest protected by aortic root potassium cardioplegia. In Group II, only aortic root potassium cardioplegia was given; in Group III, the ischemic area was perfused with potassium cardioplegic solution via a graft from the internal mammary artery (IMA) to the LAD. In Group IV, blood cardioplegic solution via the IMA-LAD graft was used. After the cross-clamp and local occlusion were removed, CPB was discontinued after an additional 45 minutes and reperfusion was continued off CPB for an additional 1 1/2 hours (total 6 hours). The ischemic area at risk was determined by injecting monastryl blue dye via the left atrium while the LAD was briefly reoccluded. After the animal had been sacrificed and the left ventricle had been sectioned, the area of myocardial necrosis was determined by nonstaining with triphenyltetrazolium chloride (TTC). For each group, the ratios of area of necrosis/area at risk (AN/AR) were calculated and postreperfusion arrhythmias were documented. Postreperfusion arrhythmias were noted in 11 of 12 animals in the beating, working heart group and only two of 24 in the combined CPB groups. The mean AN/AR was 66% +/- 2% in the beating, working heart (Group I), 59% +/- 6% after infusion of potassium cardioplegic solution into the aortic root (Group II), 57% +/- 6% with blood cardioplegia (Group IV), and 38% +/- 6.5% after global and local application of the potassium cardioplegic solution into the ischemic area (Group III). This study suggests that the reperfused ischemic myocardium will sustain less necrosis and less postreperfusion arrhythmias when the heart is protected by global and local cold potassium cardioplegia on CPB.
Acute Disease↗
Management of adults with congenital bidirectional cardiac shunts, cyanosis, and pulmonary vascular obstruction: successful operative repair in 3 patients.
Patients with congenital cardiac shunts in whom marked functional disability, cyanosis and pulmonary arterial hypertension develop have been considered inoperable or at exceedingly high risk. Three adult patients, 2 with atrial septal defect (ASD) and 1 with patent ductus arteriosus (PDA), presented with New York Heart Association class IV symptoms, bidirectional shunting with cyanosis, polycythemia, severe pulmonary hypertension, and increased pulmonary vascular resistance. Pulmonary arterial pressure did not decrease in response to administration of 100% oxygen in any patient, and 2 had lung biopsy results showing advanced pulmonary vascular obstruction. While a right-to-left shunt caused cyanosis in all patients, the net shunt was left to right (Qp/Qs greater than 1) and the resistance ratio (Rp/Rs) less than 0.5. All 3 patients survived operation, became acyanotic with normal hematocrit, and are in functional class I or II a mean of 36 months postoperatively. At repeat cardiac catheterization, pulmonary arterial pressure and resistance had decreased substantially. This high-risk group of patients with bidirectional shunts, in whom cyanosis due to pulmonary vascular obstruction and polycythemia develop and who appear to be at very high operative risk, should still be considered for surgical correction if the usual criteria for operability exist: net left-to-right Qp/Qs and Rp/Rs less than 0.50.
Adult↗
The value of the autopsy in three medical eras.
To determine whether advances in diagnostic procedures have reduced the value of autopsies, we analyzed 100 randomly selected autopsies from each of the academic years 1960, 1970, and 1980 at one university teaching hospital. In all three eras about 10 per cent of the autopsies revealed a major diagnosis that, if known before death, might have led to a change in therapy and prolonged survival; another 12 per cent showed a clinically missed major diagnosis for which treatment would not have been changed. Among 1980 autopsies, renal disease and pulmonary embolus were less common causes of death than before, but systemic bacterial, viral, and fungal infections increased significantly and were missed clinically 24 per cent of the time. The introduction of radionuclide scans, ultrasound, and computerized tomography as diagnostic procedures did not reduce the use of conventional tests in patients who subsequently died and were studied by autopsy. Over-reliance on these new procedures occasionally contributed directly to missed major diagnoses. We conclude that advances in diagnostic technology have not reduced the value of the autopsy, and that a goal-directed autopsy remains a vital component in the assurance of good medical care.
Autopsy↗
Long-term failure rate and morphologic correlations in porcine bioprosthetic heart valves.
To ascertain relations among site, incidence, and mechanisms of clinically evident failure of porcine bioprosthetic heart valves, the frequency of failure of 1,110 valves in 1,001 adult operative survivors from January 1972 to January 1982 was reviewed and correlated with the pathologic features of 22 consecutive dysfunctional valves. There were 373 mitral, 519 aortic, and 109 double replacements, yielding for study 482 mitral and 628 aortic valves at risk. Infective endocarditis occurred in 1.9% (8 mitral, 7 aortic, and 4 double). Twenty-three valves (13 mitral and 10 aortic) with documented primary dysfunction were explanted, a mean of 55 months (range 9 to 94) after surgery. The primary dysfunction rate for the 333 valves implanted for greater than or equal to 5 years was 6.8% (11 of 161) for mitral and 4.1% (7 of 172) for aortic valves. Valves implanted for less than 5 years had a failure rate of 0.7%. The actuarially determined freedom from primary valve failure was 98 +/- 1% for mitral and 98 +/- 1% for aortic valves at 5 years and 79 +/- 7% for mitral and 91 +/- 4% for aortic valves at 10 years. Recovered valves (12 mitral and 10 aortic) with detailed morphologic analysis were functioning for a mean duration of 52 months (range 12 to 87). Causes of failure included calcification-related tears in 7 (4 mitral and 3 aortic, mean 66 months), tear without calcium deposits in 4 (4 mitral, mean 44 months), cuspal stiffening without tear but with calcium deposits in 2 (1 mitral and 1 aortic, mean 80 months) and thrombosis in 1 (aortic). Late primary dysfunction was most frequently a result of degenerative processes, especially calcification, often with secondary tears, but cuspal tears in the absence of calcium deposits and thrombosis predominated at shorter intervals.
Adolescent↗
Coexistent carotid and coronary artery disease. Surgical management.
We performed simultaneous coronary artery bypass grafting (CABG) and carotid endarterectomy (CE) in 42 patients (average age, 61 years). Twenty-nine patients had preoperative transient ischemic attacks. Carotid arteriography showed stenosis (greater than 70%) in 38 subjects and extensive ulcerated lesions in two, and two emergency patients were not studied. Carotid artery dissection and sternotomy were simultaneously performed and the patients were cannulated for cardiopulmonary bypass (CPB). We undertook CE (22 left and 24 right) using EEG monitoring prior to CPB in all but one patient. The average carotid occlusion time was 25 minutes without a shunt in 23 patients and 5.5 minutes with a shunt in 19 patients. After CE, CABG was performed with an average aortic clamp time of 39 minutes and an average CPB time of 87 minutes. The operative mortality was 5% (2/42). There were no strokes or perioperative myocardial infarctions. Neurologic morbidity consisted of postoperative headache in one patient, transient upper-extremity weakness in two patients, and transient facial weakness in one patient. The average length of postoperative hospitalization was ten days. Currently, patients with symptomatic coronary artery disease and concomitant carotid bruits with positive noninvasive testing and arteriography should have simultaneous repair of these lesions.
Aged↗
Correction of intraoperative diastolic myocardial dysfunction with nifedipine.
We report the case of a 62-year-old man with severe aortic stenosis and hypertrophic cardiomyopathy, who could not be weaned from cardiopulmonary bypass after aortic valve replacement until buccal administration of the calcium-blocking agent nifedipine led to achievement of adequate hemodynamics. These observations demonstrate the importance of diastolic dysfunction in patients with hypertrophic cardiomyopathy, and suggest an important peri- and intraoperative role for calcium-blocking agents in their management. Recent hemodynamic studies have shown the importance of diastolic myocardial dysfunction in patients with hypertrophic cardiomyopathy, and demonstrated that calcium-blocking agents may enhance myocardial performance by reducing this dysfunction (Goodwin, 1982; Lorell et al., 1980, 1982; Sanderson et al., 1977). Although this new class of drugs has been increasingly used as an adjunct to cardioplegia, there is little information thus far on their application as treatment of intraoperative diastolic abnormalities. We report the case of a 62-year-old man with severe aortic stenosis and hypertrophic cardiomyopathy, who could not be weaned from cardiopulmonary bypass after aortic valve replacement until buccal administration of the calcium-blocking agent nifedipine led to an increase in cardiac output and blood pressure.
Aortic Valve Stenosis↗
Noninvasive assessment of valvular heart disease: surgery without catheterization.
Forty-one patients underwent valve surgery at our institution based solely on clinical, M-mode echocardiographic, phonocardiographic, and external pulse recording findings without preoperative cardiac catheterization. Patients with clinical evidence of coronary artery disease were excluded from the study. Preoperatively, 83% of the patients were New York Heart Association functional class III or IV. In all patients, the noninvasive evaluation was considered sufficiently diagnostic of the nature and severity of valvular heart disease to allow surgery without preoperative catheterization. In 23 of 41 cases (group 1), cardiac catheterization was not performed due to the patients' unstable hemodynamic condition at the time surgery was being considered. In the remaining 18 patients (group 2), the probability of obtaining data at catheterization that would significantly affect management decisions was thought to be low, thus not justifying the cost and potential morbidity of this procedure. In all cases, the noninvasive diagnosis was corroborated at operation; there were no unexpected findings nor deaths related to incomplete or incorrect diagnoses. Over a followup period of 4.5 +/- 1.4 years, no patient experienced signs or symptoms of ischemic heart disease. In selected patients without anginal chest pain syndromes, appropriate and successful valve surgery may be performed on the basis of combined clinical and noninvasive evaluation without the need for cardiac catheterization.
Adolescent↗
Effect of fluocarbon exchange transfusion on myocardial infarction size in dogs.
Fluosol DA (20%), a perfluocarbon with high oxygen solubility, was administered by concurrent exchange transfusion (30 ml/kg) to anesthetized open-chested adult greyhounds (n = 9) 1 hour after left anterior descending coronary ligation. Mechanical ventilation using 100% oxygen was used throughout the experiment. A second similar group (n = 9) received 0.9% normal saline solution (30 ml/kg), and a third group (n = 9) received no further intervention. Systemic, right atrial, and left atrial pressures were not altered by the exchange transfusion. Monastryl blue dye was injected through the left atrial line at 6 hours after ligation to define the area of myocardium at risk (AR); the animals were then killed and the heart was excised. The left ventricle was sliced at 5 mm intervals and stained using triphenyltetrazolium chloride, defining areas of necrosis (AN). The ratio of AN/AR and total left ventricular mass were then compared with the use of planimetry. The results were as follows: the AN/AR ratio in the 9 control animals was 90 +/- 2 (mean +/- standard error of the mean); in the 9 animals who received saline solution it was 88 +/- 2; and in the animals who received Fluosol it was 67 +/- 4 (p less than 0.01 compared with control; p less than 0.001 compared with the saline group). Fluocarbon exchange transfusion may reduce infarct size when administered after coronary occlusion.
Animals↗
Prostacyclin inhibits 5-hydroxytryptamine release but stimulates thromboxane synthesis during cardiopulmonary bypass.
The antiaggregating agent prostacyclin (PGI2) was infused into ten dogs during cardiopulmonary bypass (CPB) to minimize thrombocytopenia and platelet dysfunction. The animals were anesthetized, placed on mechanical ventilation and underwent thoracotomy. After heparinization with 300 u/kg, animals were assigned to control (n=5) or PGI2 treated groups (n=5). Thoracotomy and then CPB decreased platelet numbers to below 30,000/mm3 (p less than 0.05) and fibrinogen to less than 150 mg/dl (p less than 0.05). PGI2 at 100 ng/kg.min was infused for the 2 h period of CPB. PGI2 infusion did not prevent these changes, but did prevent platelet serotonin release. In the control group after CPB, platelet serotonin fell from the baseline value of 1.11 microgram/10(9) to 0.35 microgram/10(9) platelets (p less than 0.05). In contrast, PGI2 treatment resulted in a serotonin increase to 2.27 micrograms/10(9) platelets (p less than 0.05). Thromboxane B2 concentrations of platelets and plasma rose during CPB (p less than 0.05). Surprisingly, PGI2 infusion accentuated this rise in platelet and plasma thromboxane B2 (p less than 0.05). These data indicate that during CPB, an infusion of PGI2: 1) does not prevent thrombocytopenia; 2) increases platelet serotonin uptake despite, 3) an associated rise in platelet and plasma thromboxane B2.
6-Ketoprostaglandin F1 alpha↗
Hemodynamic evaluation of new cardiac valves.
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Cardiac Catheterization↗
Cardiopulmonary bypass during reperfusion after coronary occlusion attenuates the "no reflow" phenomenon in ischemic myocardium.
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Animals↗
The reliability of angiography in predicting quality and caliber of the distal coronary artery lumen in preparation for bypass surgery.
To determine whether coronary arteriograms accurately predict the presence of distal coronary lumena that are inadequate for bypass because of diffuse disease and/or small caliber, angiographic grading of distal lumen (DL) caliber was carried out on 867 diseased coronary arteries on which bypass was subsequently attempted. Where the DL was graded as normal, bypasses could be successfully constructed in 96% of cases. Where the general DL caliber was normal but one or more localized distal stenoses were present, bypasses could be successfully constructed in 95.6% of cases. Where the DL caliber was reduced to a mild-moderate degree angiographically, bypasses were successfully constructed in 83.6%. Where the DL had a severely reduced caliber or could not be visualized at all, bypasses were successfully constructed in 73.0%. Thus, even when a severely narrowed or totally occluded DL appears present, bypass can still be performed in almost 75% of cases. The angiographic diagnosis of a nongraftable distal segment is therefore unreliable and patients should not be denied bypass on this basis alone.
Coronary Angiography↗