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Biomedical subjects

R B Karp

Publications and source records attributed to R B Karp.

At least 91 records · Page 5Linked to original sources
PubMed1981

Hospital mortality of re-replacement of the aortic valve. Incremental risk factors.

A total of 200 aortic vale re-replacements were performed between Jan. 1, 1975, and July 1, 1979. The re-replacements (RRP) were an isolated procedure or combined with coronary artery bypass grafting or resection of ascending aortic aneurysm. Ten patients (5%) died in hospital, compared with 24 (2.9%) among 842 patients undergoing isolated or combined initial aortic valve replacement (AVR) (p = 0.12). The mode of death was cardiac failure in six of the 10 patients, hemorrhage in two (from accidents at repeat sternotomy), and neurologic deficits in two (each with innominate vein transection at repeat sternotomy repaired by ligation). There were seven (3.9%) hospital deaths among 181 first RRP (p for difference from initial AVR = 0.5), but three (15%) of 19 died after the second or third RRP (p = 0.001). By simple contingency table analysis, preoperative New York Heart Association (NYHA) Class IV increased the risk of hospital death after RRP (p = 0.002), as did prosthetic valve endocarditis (p = 0.0005) and the use of cold ischemic arrest (p = 0.03). Logistic multivariate analysis showed advanced NYHA functional class (p = 0.02), use of cold ischemic arrest (p = 0.09), and increased aortic cross-clamps time (p = 0.03) to be incremental risk factors. Recommendations for reducing hospital deaths in the event of RRP are (1) reoperate before severe hemodynamic deterioration occurs, (2) plan and conduct the operation to minimize accidents from repeat sternotomy and dissection, (3) keep aortic cross-clamp time as short as possible, and (4) employ cold cardioplegia.

Aortic Valve↗
PubMed1981

The Björk-Shiley valve: intermediate-term follow-up.

We evaluated 643 patients surviving aortic, mitral, and aortic and mitral ("double") valve replacement with the Björk-Shiley prosthesis from 1 to 72 months (median 38 months) postoperatively. Intermediate-term survival rate was similar to that reported for other prosthetic and bioprosthetic devices. Factors unrelated to the device, but related to preoperative patient characteristics or intraoperative or early postoperative events, had important association with late survival rate. These included previous valve replacement, concomitant ventricular aneurysm resection, black race, preoperative functional class, method of myocardial protection, duration of ischemic arrest, ventricular arrhythmias, and double valve replacement. Concomitant coronary artery bypass grafting and the type of valve lesion had no effect on survival prognosis. Freedom from thromboembolism was equal to or superior to other devices, but valve thrombosis occurred 16 times in 15 patients and caused 13 deaths. Improvement in New York Heart Association (NYHA) functional class occurred in the majority of patients. We conclude that the Björk-Shiley valve is durable and effective, but, as with other devices, is associated with problems of thromboembolism and thrombosis. Intermediate-term survival is related also to non-device, patient-associated characteristics.

Adolescent↗
PubMed1981

Dissection of the aorta.

Recent experience indicates that the treatment of acute aortic dissection is satisfactory in about 75 percent of cases. Most centers have moved to early operations for those dissections involving the ascending aorta and a combination of anti-impulse therapy and expectant operative treatment for those dissections involving only the descending aorta. Physicians seeing acute circulatory problems should be aware of catastrophic nature of aortic dissection and of the available methods for its diagnosis and treatment.

Aortic Dissection↗
PubMed1981

Incremental risk factors for spinal cord injury following operation for acute traumatic aortic transection.

Of 35 patients operated upon for acute traumatic transection of the upper descending thoracic aorta between 1967 and March 31, 1980, 33 had sufficient information for us to analyze the incidence of spinal cord injury (paraplegia or paresis). This event occurred in eight patients. Multivariate analyses indicated that spinal cord injury was more likely to occur with long aortic cross-clamp times (p = 0.08) when no shunt was employed to perfuse the distal aorta during cross-clamping. The data suggest that if an aortic cross-clamp time exceeding about 30 minutes is anticipated, a shunt should be employed during aortic cross-clamping.

Acute Disease↗
PubMed1980

Pathogenesis of paroxysmal hypertension developing during and after coronary bypass surgery: a study of hemodynamic and humoral factors.

A prospective study of hypertension first appearing during and after saphenous vein bypass coronary surgery was performed in 28 patients to examine the incidence, hemodynamics and mechanism of this problem. In 15 patients (54 percent) new hypertension developed (mean arterial pressure greater than 107 mm Hg), characterized by increased peripheral vascular resistance and unchanged cardiac output within 1 hour after surgery. These 15 patients had a longer history of angina of greater severity, but also had relatively well preserved ventricular myocardium. Because plasma renin activity was depressed in patients in the hypertensive group, activation of the renin-angiotensin system was not important in the pathogenesis of this postoperative hypertension. The expected decrease in total peripheral resistance at the onset of cardiopulmonary bypass was observed in all patients, but later during bypass the peripheral resistance increased in all patients in association with a rise in plasma epinephrine levels. Patients who had hypertension postoperatively had a greater increase in arterial pressure and total peripheral resistance during cardiopulmonary bypass than did those with normal postoperative blood pressure. An elevation in plasma epinephrine and norepinephrine concentration, suggesting enhanced sympathoadrenal responsiveness to the challenge of cardiopulmonary bypass, was characteristic of the hypertensive group. This evidence of enhanced sympathetic activity during surgery may be a useful predictor of the development of postoperative hypertension.

Blood Pressure↗
PubMed1980

Clotted hemopericardium with the hemodynamic characteristics of constrictive pericarditis.

Cardiac catheterization in a patient 4 weeks after coronary arterial bypass surgery demonstrated the typical hemodynamic findings of constrictive pericarditis, which completely resolved after removal of 500 ml of clotted pericardial blood. The pericardium was not responsible for the findings because it was left in place. This case demonstrates that clotted hemopericardium may mimic constrictive pericarditis.

Aged↗
PubMed1980

Considerations in selection and management of patients undergoing valve replacement with glutaraldehyde-fixed porcine bioprotheses.

From November, 1973, through June, 1978, 428 operations in 425 patients were performed for replacement of aortic, mitral, or aortic plus mitral valves, utilizing 277 Hancock and 180 Carpentier-Edwards bioprostheses. Actuarially determined survival at 36 months was similar for all three groups and compared favorably with our experience with the Björk-Shiley prosthesis. Certain patient-related variables influencing late survival were identified by multivariate analysis and included previous operation for congenital heart disease, coronary artery bypass grafting in nonaortic valve replacement, race (black), age at operation, and New York Heart Association Functional Class. A small but definite incidence of thromboembolism occurred in all three groups, again similar to our experience with the Björk-Shiley prosthesis. Multivariate analysis identified four factors influencing risk of thromboembolism: previous cardiac operation, age, double-valve replacement, and rhythm at discharge. Valve degeneraation occurred, primarily in children and young adults. Over the medium term, the porcine bioprosthesis compared favorably with mechanical prostheses in terms of survival, function, and thromboembolism. Certain patient-related variables affecting survival may be modified by earlier surgical intervention.

Adolescent↗
PubMed1980

Replacement of the ascending aorta and aortic valve with a composite graft. Results in 86 patients.

We reviewed our entire experience with composite graft replacement of the ascending aorta and aortic valve during a 63 month interval ending in December, 1979. Anuloaortic ectasia was the most common indication for operation, followed by aortic dissection (acute and chronic). Hospital mortality was 5% and was related to the preoperative functional status and the duration of intraoperative myocardial ischemia. Reoperation on the ascending aorta for reasons other than postoperative hemorrhage was required in five of the 82 hospital survivors (6%). By actuarial analysis, 90% of hospital survivors were free of any reoperation on the ascending aorta or aortic valve three years postoperatively, and 93% were free of reoperation related specifically to the composite graft. Pseudoaneurysms at the coronary ostia or distal aortic anastomosis were observed in five of 16 patients having postoperative angiography. One of the five patients has required reoperation. Follow-up has averaged 23.5 months (range: 0.2-60 months). Three year actuarial survival for the 86 patients was 81%, for 44 patients with anuloaortic ectasia was 88%, and for 31 patients with aortic dissection was 83%. Composite graft replacement of the ascending aorta and aortic valve is a satisfactory alternative to supracoronary graft replacement and aortic valve replacement. It offers the advantage of excluding all aneurysmal tissue from the aortic anulus to the innominate artery, thereby eliminating the potential for later development of aneurysms of the sinuses of Valsalva, a known complication of the supracoronary technique. It is the method of choice for patients with anuloaortic ectasia and cephalad displacement of the coronary ostia. It is suitable for many patients with acute or chronic dissection and for patients with sinuses of Valsalva aneurysms following previous operations on the ascending aorta or aortic valve.

Adolescent↗
PubMed1979

Multiple cardiovascular injuries and motor vehicle accidents.

A patient sustained blunt chest trauma in a motor vehicle accident. Cardiovascular trauma was initially obscured by more obvious orthopedic injuries. Thoracic aortic transection with false aneurysm formation was discovered incidentally during cardiac catheterization for traumatic tricuspid insufficiency. Successful repair of both lesions was subseqeuntly performed. This case demonstrates the difficulty in recognizing cardiovascular trauma in survivors of motor vehicle accidents and emphasizes the need for an aggressive diagnostic approach with consideration of coexisting injuries in patients who have sustained blunt chest trauma.

Accidents, Traffic↗
PubMed1979

Combined aortic valve replacement and myocardial revascularization: results in 220 patients.

During a 7.5-year period ending in June 1977, 220 patients underwent combined aortic valve replacement and myocardial revascularization. Early (30-day) mortality was 5.4% (12 patients), and was significantly affected by the development of perioperative myocardial infarction. For 23 patients with electrocardiographic and enzymatic evidence for definite infarction, hospital mortality was 17%; for 66 patients with probable infarction mortality was 5%; and for 116 patients without evidence for infarction mortality was 3%. The difference in mortality between the definite and no infarction groups was significant (p less than 0.01). The incidence of perioperative infarction was influenced by the type of myocardial protection employed during the operative procedure. Definite infarction occurred in 24% of 41 patients who had mild (28-32 degrees C), intermittent hypothermic coronary perfusion, in 9% of 142 patients with hypothermic ischemic arrest (myocardial temperature 20 to 27 degrees C) and in none of 22 patients with hypothermic, potassium-induced cardioplegia (myocardial temperature 8--18 degrees C). The difference in the rate of infarction between the coronary perfusion and the two hypothermic ischemic arrest groups was significant (p less than 0.01). The mean duration of followup for 100% of the hospital survivors was 22.5 months. Cumulative survival was 88% at 1 year and 77% at 3 years. These figures do not differ significantly from those for patients without coronary artery disease having isolated aortic valve replacement in our institution, and are superior to those reported for patients with coronary and aortic valve disease undergoing only aortic valve replacement. We conclude that combined aortic valve replacement and myocardial revascularization should be performed in all patients in whom the lesions coexist. Hypothermic ischemic arrest, preferably in combination with potassium-induced cardioplegia, provides the most myocardial protection during operation.

Adult↗
PubMed1979

The echocardiogram after pericardiectomy.

Many factors may affect the interventricular septal motion. This study measures the effect of pericardiectomy on septal motion in 9 patients who were evaluated 1 week to 58 months after pericardiectomy. Echocardiography was performed with the patient in recumbent position with the special care to record motion of the muscular septum and not that of the aorta. No patient had left bundle branch block, angina, myocardial infarction, pericardial effusion or right ventricular volume overload. Septal motion was paradoxical in 7, normal in 1 and could not be evaluated 1 patient. The mean value of the right ventricular internal dimension was normal. Two of 9 patients had technically satisfactory echocardiograms preoperatively. Septal motion was normal in both, and both developed paradoxical septal motion postoperatively. We conclude that paradoxical septal motion pericardiectomy, but in contrast with other causes of this finding right ventricular internal dimension remains normal.

Adult↗
PubMed1979

Hemodynamic effects of aortic clamping and decompression with a temporary shunt for resection of the descending thoracic aorta.

To assess the effects clamping of the proximal thoracic aorta and of subsequent decompression with a temporary shunt on cardiac function during resection of aneurysms of the descending thoracic aorta, mean arterial (MAP), central venous (CVP), mean pulmonary arterial (MPAP), and pulmonary capillary wedge pressures (PCWP), as well as cardiac index (CI), were measured in eight patients at baseline, 2 minutes after clamping the aorta beyond the left carotid or left subclavian artery, and 2 minutes after opening the shunt. Following clamping, MAP, CVP, and PCWP increased significantly (P less than 0.05), while CI decreased significantly, an average of 29%, and heart rate remained unchanged. After opening the shunt, all pressures returned to baseline levels. CI increased, but remained below the baseline level in seven of the eight patients (P less than 0.05). Our data indicate that significant deterioration of left ventricular performance results from clamping and that the deleterious effects can be reversed by use of a temporary shunt. They support the recommendation of proximal aortic decompression during thoracic aneurysmectomy.

Adult↗
PubMed1978

Characterization of atrial fibrillation in man: studies following open heart surgery.

The nature of localized atrial activation during atrial fibrillation was characterized in 34 patients following open heart surgery. Bipolar atrial electrograms (AEG) recorded in each patient with atrial fibrillation exhibited a myriad of sizes, shapes, polarities, amplitudes, and beat-to-beat intervals. On the basis of the AEG morphology and the nature of its baseline, we have classified the recordings into four Types. Type I was characterized by discrete AEG complexes separated by an isoelectric baseline free of perturbation, Type II by discrete AEG complexes but with perturbations of the baseline between complexes, Type III by AEGs which failed to demonstrate either discrete complexes or isoelectric intervals, and Type IV in which AEGs of Type III alternated with periods characteristic of Type I and/or Type II. In 22 patients, the AEGs were recorded a second time, and in 11 of these patients the type of atrial fibrillation changed between the first and second recording period. An atrial flutter-fibrillation pattern in the ECG was associated with a relatively ordered atrial activation pattern and a relatively slow atrial rate. Human atrial fibrillation is not an electrophysiologically homogeneous process when compared among different patients or ad seriatim in the same patient.

Adult↗
PubMed1978

Treatment of infective endocarditis: a 10-year comparative analysis.

The results of surgical and non-surgical treatment of active infective endocarditis in 182 patients over a 10-year period were analyzed. Heart failure, annular and myocardial abscesses, heart block, and coronary embolism, seen most frequently with staphylococcal and fungal endocarditis, were the primary causes of death in both native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE). In NVE, surgery significantly improved the survival in patients with moderate or severe heart failure (P less than 0.05) and in all patients with staphylococcal endocarditis (P less than 0.03). In PVE, surgery significantly influenced survival in patients with moderate or severe heart failure (P less than 0.05) and in the entire group with late PVE (P less than 0.01). Early surgery is recommended for patients with native valve endocarditis and moderate or severe heart failure; those patients with staphylococcal NVE, regardless of hemodynamic state, should undergo early valve replacement. Early surgery is recommended for PVE patients with moderate or severe heart failure. We also recommend early valve replacement for early and late staphylococcal PVE.

Adolescent↗