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Biomedical subjects

L H Cohn

Publications and source records attributed to L H Cohn.

At least 73 records · Page 4Linked to original sources
PubMed1996

Long-term follow-up after surgical repair of ostium primum atrial septal defects in adults.

OBJECTIVES: We sought to determine the long-term survival rates and defect-related morbidity of adult patients who undergo surgical repair of an ostium primum atrial septal defect. BACKGROUND: The natural history of patients undergoing such surgical repair in adulthood remains unclear. METHODS: We followed up 33 patients who underwent surgical correction of an ostium primum atrial septal defect at our institution at a mean age of 42 years (range 20 to 73); 12 of these patients were > 50 years old at the time of operation. Four patients had moderate preoperative exercise incapacity (New York Heart Association functional class > II) and six had atrial fibrillation. Nine and four patients, respectively, had a preoperative mean pulmonary artery pressure > 25 mm Hg or pulmonary vascular resistance > 4 Wood U. Autologous pericardium was used to patch the defect in 30 patients (91%). Mitral valvuloplasty, consisting of cleft repair (n = 10), and mitral valve replacement (n = 2) were performed selectively. RESULTS: There were no operative deaths. At a mean follow-up interval of 5.3 years (range 1 to 18.2), all 28 surviving patients are free of exercise limitation (functional class 1). Late postoperative deaths occurred in five patients (15%) and were related to myocardial infarction, stroke, hepatic failure, renal failure or sepsis. Reoperation within the 1st postoperative year was required in two patients (6%) because of a residual ostium primum defect in one and severe mitral regurgitation in the other. The presence of advanced age at operation, symptoms, atrial arrhythmias, mitral regurgitation or moderately increased pulmonary vascular resistance did not predict late postoperative mortality, complications or functional capacity. CONCLUSIONS: An ostium primum defect can be repaired in adult patients with the expectation of excellent long-term results, independent of age at operation and preoperative mitral valve function and despite the presence of atrial fibrillation or moderately elevated pulmonary vascular resistance.

Adult↗
PubMed1996

Current incidence and determinants of perioperative myocardial infarction in coronary artery surgery.

Increasingly, patients undergoing coronary artery bypass grafting (CABG) are elders, have had previous CABG, and have poor left ventricular function. To evaluate determinants of perioperative myocardial infarction (PMI) after isolated CABG, 499 consecutive patients were reviewed. Definite PMI (total peak creatine kinase [CK] > 700 U/L, creatine kinase MB [CK-MB] > 30 ng/ml, and new pathologic electrocardiographic Q waves) occurred in 25 patients (5.0%) and probable PMI (total peak CK > 700 U/L, CK-MB > 30 ng/ml, and a new wall-motion abnormality) occurred in 10 (2.0%) patients. According to multivariate logistic regression analysis, independent risk factors for definite or probable PMI (adds ratios; 95% confidence intervals) were emergency surgery (3.1; 1.1 to 8.4; p = 0.003), aortic cross-clamp time > 100 minutes (4.2; 1.6 to 11.2; p = 0.004), myocardial infarction in the preceding week (2.6; 1.0 to 6.4; p = 0.04), and previous revascularization (2.4; 1.1 to 5.2; p = 0.02). In conclusion, both preoperative and intraoperative factors influence the risk of PMI after CABG. Despite changes in the profile of patients undergoing CABG, the incidence of PMI in this tertiary center is comparable with that found in earlier series, probably because of improvements in surgical techniques and postoperative care.

Aged↗
PubMed1996

Guidelines for reporting morbidity and mortality after cardiac valvular operations. The American Association for Thoracic Surgery, Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity.

At the request of the Councils of The Society of Thoracic Surgeons (STS) and The American Association for Thoracic Surgery (AATS) the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity "revisited" the "Guidelines" published in September 1988 [1-3]. The purpose of the review was to update and clarify definitions within the guidelines and to consider recommendations made by others [4, 5]. The variety of cardiac valvular procedures has expanded since 1988; therefore, in this document the term "operated valve" indicates prosthetic and bioprosthetic heart valves of all types: operated or repaired native valves and allograft and autograft valves. The term "operated valve" includes any cardiac valve altered by a surgeon during an operation. Much morbidity and mortality is a direct consequence of the interaction between the patient and operated valve(s), although patient variables (e.g., age, degree of coronary arterial disease, follow-up care) may be more responsible for outcomes than an operated valve. However, no set of guidelines can identify all possible patient factors that may affect morbidity and mortality. General agreement regarding the following definitions of terms and suggestions for reporting data do not preclude more detailed analyses or constructive recommendations and investigators are encouraged to identify relevant patient factors in addition to factors related to operated valves.

Documentation↗
PubMed1996

Aprotinin in primary valve replacement and reconstruction: a multicenter, double-blind, placebo-controlled trial.

BACKGROUND: Patients having cardiac operations often require blood transfusions. Aprotinin reduces the need for blood transfusions during coronary artery bypass graft operations. To determine the safety and effectiveness of aprotinin in reducing the use of allogeneic blood and postoperative mediastinal chest tube drainage, we studied 212 patients undergoing primary sternotomy for valve replacement or repair. METHODS: This study was multicenter, randomized, prospective, double-blind, and placebo-controlled. Patients received high-dose aprotinin (n = 71), low-dose aprotinin (n = 70), or placebo (n = 71). The study medication was given as a loading dose followed by a continuous infusion and pump prime dose. Heparin administration was standardized. Transfusions, postoperative mediastinal shed blood, and adverse events were tracked. RESULTS: Demographic profiles were similar among the treatment groups. Aprotinin did not decrease the percentage of patients receiving transfusions when compared with placebo (high-dose aprotinin, 63%, p = 0.092; low-dose aprotinin, 52%, p = 0.592; placebo, 48%). Aprotinin was associated with a reduction in the volume of mediastinal shed blood (high-dose aprotinin vs placebo, p = 0.002; low-dose aprotinin vs placebo, p = 0.017). Adverse events were equally distributed among the treatment groups except for postoperative renal dysfunction (high-dose aprotinin, 11%; low-dose aprotinin, 7%; placebo, 0%; p = 0.01). A disproportionate number of patients in the high-dose aprotinin group with postoperative renal dysfunction also had diabetes mellitus. CONCLUSIONS: Aprotinin treatment in this population did not reduce allogeneic blood use, although there were significant reductions in the volume of mediastinal shed blood.

Aprotinin↗
PubMed1996

Transmyocardial laser revascularization: operative techniques and clinical results at two years.

OBJECTIVES: A new technique, transmyocardial laser revascularization, provides direct perfusion of ischemic myocardium via laser-created transmural channels. From 1993 to 1995, we have treated 20 patients (mean age 61 years, four women and 16 men) with transmyocardial laser revascularization. Preoperatively, the average angina class was 3.7. The patients were screened before the operation by a technetium sestamibi perfusion scan to identify the location and extent of their reversible ischemia. METHODS: Operative exposure is gained via a left anterior thoracotomy. With the use of a 850-watt carbon dioxide laser, an average of 21 +/- 4 channels were created in 22 minutes with a total operative time of less than 2 hours. RESULTS: The in-hospital mortality was two of 20 patients. Three additional patients died after discharge. After an accumulated 172 patient-months (mean follow-up 11 +/- 8 months, range 1 to 26 months), the mean angina class is I (p = 0.01). Postoperative sestamibi scans were obtained at 3, 6, and 12 months. Using the septum as a control and comparing the postoperative results with the preoperative baseline, we noted a significant improvement in perfusion particularly in the areas of reversible ischemia. CONCLUSION: These early results indicate that transmyocardial laser revascularization is a simple operative technique that may improve myocardial perfusion and provide angina relief for patients in whom standard methods of revascularization is contraindicated.

Aged↗
PubMed1996

Guidelines for reporting morbidity and mortality after cardiac valvular operations.

At the request of the Councils of the Society of Thoracic Surgeons (STS) and the American Association of Thoracic Surgery (AATS) the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity reviewed the "Guidelines" published in September 1988 [3, 7, 8]. The purpose of the review was to update and clarify definitions within the guidelines and to consider recommendations made by other [2, 11]. The variety of cardiac valvular procedures has expanded since 1988; therefore, in this document the term "operated valve" indicates prosthetic and bioprosthetic heart valves of all types, operated or repaired native valves and allograft and autograft valves. The term "operated valve" includes any cardiac valve altered by a surgeon during an operation. Much morbidity and mortality is a direct consequence of the interaction between the patient and operated valve(s), although patient variables (e.g., age, degree of coronary arterial disease, follow-up care, etc.) may be more responsible for outcomes than an operated valve. However, no set of guidelines can identify all possible patient factors that may affect morbidity and mortality. General agreement regarding the following definitions of terms and suggestions for reporting data do not preclude more detailed analyses or constructive recommendations and investigators are encouraged to identify relevant patient factors in addition to factors related to operated valves. Purpose The purpose of these guidelines is to facilitate the analysis and reporting of results of operations on diseased cardiac valves. The definitions and recommendations that follow are guidelines, not standards, and are designed to facilitate comparisons between the experiences of different surgeons who treat different cohorts of patients at different times with different techniques and materials.

Data Collection↗
PubMed1996

Reduced mortality and morbidity for ascending aortic aneurysm resection regardless of cause.

BACKGROUND: This study was done to answer the question, "What is the current risk of resection of ascending aortic aneurysms regardless of acuity or cause?" METHODS: One hundred fifteen consecutive patients who underwent ascending aortic aneurysm repair from January 1, 1990, to July 1, 1995, were retrospectively reviewed, excluding those with acute ascending aortic dissection. The mean age was 59 years; 55% were male. Concomitant procedures included coronary artery bypass in 23 (20%) and arch repair in 12 (10%). In group 1, 54 patients had replacement of the aortic valve, root, and ascending aorta with a valve-graft conduit using the "Bentall" technique, and of these 19 (35%) had Marfan's syndrome. In group II, 44 patients had separate aortic valve repair or replacement and supracoronary ascending aortic replacement. In group III, 17 patients had supracoronary ascending aortic replacement, without aortic valve operation. Operative techniques included frequent use of (1) intraoperative transesophageal echocardiography or epiaortic ultrasound scanning of the ascending and descending thoracic aorta to help guide arterial cannulation, avoid atherosclerotic embolization, and assess the repair; (2) antegrade and retrograde multidose cold blood cardioplegia for myocardial protection; (3) exclusion and button anastomotic techniques to ensure secure suture lines; (4) antifibrinolytic agents and collagen-impregnated aortic grafts to reduce bleeding; and (5) deep hypothermic circulatory arrest and the open distal anastomotic technique in patients with distal ascending and arch aortic disease. RESULTS: Operative mortality overall was 2/115 (1.7%). Mortality was 1/54 (1.8) in group I and 1/44 (2%) in group II, and there was no mortality in group III. The overall postoperative morbidity was 3% due to bleeding, 2% due to stroke, and 1% due to myocardial infarction. The length of stay in the past year has decreased to less than 7 days. CONCLUSIONS: The current risk for ascending aortic aneurysm repair is low (< 2%) whether or not the aortic root or valve also needs repair, regardless of the cause of the aneurysm.

Adult↗
PubMed1995

Prevention of venous thrombosis after coronary artery bypass surgery (a randomized trial comparing two mechanical prophylaxis strategies).

Although venous thrombosis may occur often after coronary artery bypass grafting, prophylaxis with low-dose heparin is rarely used due to the risk of bleeding. Therefore, we compared the efficacy of 2 mechanical regimens of prophylaxis against deep vein thrombosis (DVT). Consecutive patients undergoing coronary artery bypass without concomitant valve surgery or coronary endarterectomy were randomized to either a more intensive regimen of intermittent pneumatic compression (IPC) plus graduated compression stockings (GCS) versus standard compression stockings alone. Of 611 patients screened, 184 were excluded due to peripheral vascular disease, postoperative intraaortic balloon support, or immediate postoperative anticoagulation. An additional 83 patients refused consent, leaving 172 in each prophylaxis group. The primary study end point was DVT diagnosed by a predischarge leg ultrasound examination performed on postoperative days 4 to 6. Of 344 patients enrolled, 330 (96%) underwent predischarge ultrasonography. DVT was detected in 19% of patients assigned to IPC plus stockings versus 22% assigned to GCS alone (95% confidence interval for the difference, -11% to 6%, p = 0.62). The addition of IPC did not add significant incremental benefit to GCS alone for DVT prophylaxis among patients undergoing coronary artery bypass surgery.

Aged↗
PubMed1995

Determinants of early mortality and late survival in mitral valve endocarditis.

BACKGROUND: Infective mitral valve endocarditis continues to be a significant surgical challenge. The objective of this study was to examine our experience with mitral valve endocarditis surgery and identify determinants of early mortality and late survival. METHODS AND RESULTS: Over a 24-year period, mitral valve surgery was performed in 96 patients for infective mitral valve endocarditis. Patient age ranged from 20 to 78 years (median age, 52 years). There were 44 women (46%), and 48 of the 96 patients (50%) were in New York Heart Association functional class IV before surgery. Native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE) were present in 72 patients (75%) and 24 patients (25%), respectively. Surgery during the active phase of endocarditis (AE) was required in 60 patients (62%) and during the healed phase (HE) in 36 (38%). The main indications for surgery in the AE group were congestive heart failure (60%), active sepsis (67%), peripheral emboli (47%), and acute renal failure (20%), and for the HE group the main indication was progressive congestive heart failure (69%). The overall operative mortality was 5.2%. Multivariate logistic regression analysis identified PVE (odds ratio [OR] 22.5; +/- 95% confidence interval, CI, 1.9 to 268; P = .014) and an associated procedure (OR 13.3; +/- 95% CI, 1.5 to 120; P = .021) to be independent predictors for early mortality. Follow-up was 97% complete, with a median of 3.5 years. Overall 5- and 10-year survivals were 83 +/- 4% and 63 +/- 8%, respectively. Multivariate analysis for late mortality identified PVE to be a significant predictor of late mortality (hazards ratio = 3.1, +/- 95% CI, 1.4 to 6.8, P = .006). There were no significant differences in long-term morbidity results among the various subsets of mitral valve endocarditis. CONCLUSIONS: Mitral valve surgery for infective endocarditis is a significant high-risk procedure for PVE and when combined with associated procedures. The activity of endocarditis does not appear to have any influence on early mortality or long-term survival.

Adult↗
PubMed1995

Shed whole blood autotransfusion during aortic aneurysm operation with a modified collection infusion system.

We describe a modified shed whole blood collection and autotransfusion system that allows several options for the processing and autotransfusion of shed blood: use of the Cell Saver (Haemonetics, Braintree, MA) or the ultrafiltration of collected blood, and the autotransfusion of unprocessed shed whole blood. The system has proved useful for transfusion in the setting of thoracic aortic operations, and we describe here our experience in 5 patients undergoing resection of a descending thoracic aortic aneurysm in whom this system was used.

Aged↗
PubMed1995

Excision of focal aortic arch atheroma using deep hypothermic circulatory arrest.

A 68-year-old woman who had a stroke was found by transesophageal echocardiography to have two focal areas of pedunculated atherosclerosis in the arch of her aorta. Using echocardiographic imaging for guidance in aortic cannulation placement and deep hypothermic circulatory arrest, we removed the localized atheromata from the otherwise relatively normal aorta. She had an uneventful recovery. With the more frequent identification of discrete areas of aortic atherosclerosis as a result of transesophageal echocardiography, this procedure may become the standard by which to treat this problem.

Aged↗
PubMed1995

New technique measures decreased transmural myocardial pressure in cardiomyoplasty.

BACKGROUND: We introduce the use of a fluid-filled balloon, interposed between myocardium and latissimus dorsi (LD), as a new technique to measure transmural myocardial pressure in an acute goat model of dynamic cardiomyoplasty. METHODS: A half-ellipsoidal balloon, composed of polychloryl vinyl layers, was sutured to the atrioventricular groove in 5 goats, thereby completely enveloping both ventricles. Left LD dynamic cardiomyoplasty was then performed, anchoring the LD to the felt sewing skirt of the balloon so that the LD completely covered the balloon. Left ventricular pressure and balloon pressure were measured with the stimulator in the 1:2 mode as balloon volume was varied. RESULTS: Average transmural myocardial pressure, defined as left ventricular pressure minus balloon pressure, decreased from 34.4 mm Hg to 15.6 mm Hg during stimulator-on beats (p < 0.05). CONCLUSION: These results support the conclusion that dynamic cardiomyoplasty unloads the left ventricle by decreasing wall stress. Furthermore, transmural myocardial pressure decreased more when balloon volume was increased, implying that the LD sarcomere length has an effect on wall stress. A balloon may therefore allow optimization of LD sarcomere length and thus assisted cardiac performance.

Animals↗
PubMed1995

Recovery and viability of an acute myocardial infarct after transmyocardial laser revascularization.

OBJECTIVES: The short- and long-term effectiveness of transmyocardial laser revascularization was evaluated in the setting of an acute myocardial infarction. BACKGROUND: Theoretically, transmyocardial laser revascularization allows direct perfusion of the ischemic area as ventricular blood flows through the channels to the myocardium. METHODS: Infarcts were created by coronary occlusion in 30 sheep. Eighteen of these sheep were studied to assess short-term efficacy. The infarct was reperfused after 1 h by either removing the occlusion or by laser drilling using a high power carbon dioxide laser. The occlusions were left in place for the control group. To monitor regional recovery, percent systolic shortening was measured. To evaluate long-term effectiveness, 12 additional sheep underwent creation of an infarct. Six were treated with the laser, and six were untreated. The animals were restudied 30 days later. RESULTS: In the short-term experiment, the control and reperfusion groups exhibited no recovery of regional contractility. The laser group demonstrated improvement throughout the recovery period. There was a significant difference in the area of necrosis within the same area at risk (reperfusion group 44 +/- 6% and control group 39 +/- 5% vs. laser group 6 +/- 2%). After 30 days, none of the control animals showed evidence of contraction in the infarct, whereas the laser-treated animals did. Histologic analysis of the laser-treated infarcts revealed patent channels surrounded by viable myocardium. The control-group infarcts were necrotic and scarred. CONCLUSIONS: On the basis of both short- and long-term improved contractility, as well as diminished necrosis in the area at risk, these results indicate that transmyocardial laser revascularization may be an alternative method of treating ischemic heart disease.

Animals↗
PubMed1995

Thoracic Surgery Workforce Report. The fourth report of the Thoracic Surgery Workforce Committee of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons.

To determine demographics, practice patterns, and work volume of North American thoracic surgeons, we sent a detailed survey to all members of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons between January and May 1993 to determine data for 1992; 3049 of 3487 (87%) thoracic surgeons responded and 2677 (88%) were in active practice. Ninety-seven percent were male and 3% female, with a mean age of 52 years. Sixty-five percent considered fee-for-service as their primary compensation mode. Only 24% do isolated subspecialty work: 2% pediatric cardiac surgery. 10% general thoracic surgery, and 12% adult cardiac surgery. Seventy-six percent of respondents do both cardiac and thoracic operations. Workload data for adult cardiac, pediatric cardiac, general thoracic, peripheral vascular, and pacemaker operations were requested. Volume data were cross-correlated with age, 10 geographic regions including Canada, type of practice, and type of compensation and were cross-checked by hospital discharge data for 1992. These data were compared with data from similar surveys performed in 1976, 1980, and 1985, under the auspices of the same two societies; these latter surveys used diplomates of the American Board of Thoracic Surgery as their database. Workloads have increased over previous surveys. Most surgeons do a wide variety of thoracic operations, and exclusive designations are in the minority.

Aged↗
PubMed1995

The effect of pathophysiology on the surgical treatment of ischemic mitral regurgitation: operative and late risks of repair versus replacement.

Operative correction of ischemic mitral regurgitation (IMR) is associated with high risk approach. The objective of this retrospective study was to examine the interaction between the various underlying pathophysiologic mechanisms, the operative procedure, and their influence on short- and long-term outcomes. Over a 10-year period starting January 1984, mitral valve repair or replacement was performed on 150 patients with IMR. The age range was 42-86, mean 67, years; 71 (47%) were females; 139 (93%) were in NYHA functional class III or IV; 23 (15%) were reoperations; and 30 (20%) were in atrial fibrillation. Functional IMR due to annular dilatation or restrictive leaflet motion was present in 106 (71%), and structural IMR due to ruptured chordae or papillary muscle in 44 (29%). Mitral valve repair was performed in 94 (63%) with an annuloplasty ring employed in 80 (85%) patients. Mitral valve replacement was performed in 56 (37%), with 40 (71%) receiving a bioprosthesis (32 Hancock and 8 Carpentier-Edwards valves) and 16 (29%) a St. Jude valve. Coronary artery bypass graft surgery was performed in 139 (93%) patients. The overall operative mortality (OM) was 14/150 (9.3%). The OM for repair was 9.5% compared to 8.9% for replacement (P = NS). There was higher OM in the elderly, particularly in the repair group (P = 0.053), and a trend towards reduced OM in the recent years of the study (P = NS). No predictors of OM were identified by multivariate logistic regression analysis. Long-term follow-up was 98% complete and ranged from 2-120, mean 31.2, months for a total of 935 patient-years. The overall 5-year survival rate was 71 +/- 6%, with 91 +/- 5% for the replacement group compared to 56% +/- 10% for the repair group (P = 0.01). The functional subset of IMR who had a repair had the worse long-term survival (43 +/- 13%) compared to the structural/repair (76 +/- 13%) and structural/replacement groups (89 +/- 8%), and 92 +/- 7% for the functional/replacement group ((P = 0.0049). Multivariate logistic regression analysis identified the functional/repair group (hazards ratio 4.4; +/- 95%, confidence interval 1.6, 11, (P = 0.0031); and earlier years of surgery (hazards ratio 4.7; +/- 95% confidence interval 1.021; (P = 0.046) to be predictors of worse long-term survival. These results suggest that, in IMR, the underlying responsible pathophysiologic mechanisms appear to be the major determinants of survival, rather than the choice of the operative procedure.

Adult↗