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Biomedical subjects

R L Prager

Publications and source records attributed to R L Prager.

At least 19 recordsLinked to original sources
PubMed2001

Prophylactic mitral reconstruction for mitral regurgitation.

BACKGROUND: Mitral regurgitation (MR) will produce myocardial dysfunction. The goal of this study was to review outcomes of mitral valve reconstruction in asymptomatic patients with severe MR. METHODS: From 1992 to 2000, 93 asymptomatic patients with degenerative disease and severe MR underwent mitral valve reconstruction. Mean preoperative left ventricular internal diameter diastole was 56 +/- 8 mm and ejection fraction was 60% +/- 6%. Mean age was 47 +/- 10 years and mean follow-up 23 +/- 27 months. All patients underwent complex reconstruction. RESULTS: There were no deaths and two late reoperations. One was for systolic anterior motion of the anterior leaflet of the mitral valve requiring valve replacement and one for hemolysis requiring re-repair. There was one perioperative transient ischemic attack and no late thromboembolic events. At follow-up all but 1 patient remains in NYHA class I and all had no MR except in 2 patients at 63 and 89 months. CONCLUSIONS: Mitral valve reconstruction for "asymptomatic" MR can be performed with no mortality and low morbidity before development of left ventricular dysfunction. Early prophylactic repair is advocated in the presence of severe MR if valve reparability is assured.

Adult↗
PubMed2001

Upper extremity venous gangrene following coronary artery bypass. A case report and review of the literature.

Acute symptomatic upper extremity deep vein thrombosis (DVT) are estimated to account for only 2-4% of all deep vein thrombosis. Upper extremity DVT leading to phlegmasia cerulea dolens (PCD) occurs in an estimated 2-5% of these cases. Progression of PCD to venous gangrene is extremely rare with only 16 previously reported cases in the literature. Only 7 of the cited cases document significant tissue loss. This report describes a 61-year-old male who developed upper extremity DVT complicated by PCD which led to venous gangrene and limb loss.

Amputation, Surgical↗
PubMed2001

Reoperation for Freestyle stentless aortic valves.

Ten patients who initially underwent Freestyle stentless aortic valve implantation required reoperation. The goal of this study was to describe the reoperative techniques used and to review the outcomes of reoperation in patients with Freestyle stentless aortic valves. From September 1992 to April 2001, at the University of Michigan, a total of 552 Freestyle stentless aortic valves were implanted, and in 10 (1.8%) of these patients (7 men, 3 women) a reoperation was required. The mean age at the time of the initial implantation was 53.5 +/- 14.1 years. Implantation techniques included both modified inclusion root (7) and inclusion root (3). Reasons for reoperation included endocarditis (7), aortic aneurysm (1), valve dehiscence (1), and subvalvular outflow tract obstruction (1). Eight patients underwent homograft reimplantations and in 2 Freestyle reimplantations. In all cases, the previous aortotomy was re-entered, the pseudoendothelial layer over the distal suture line of the noncoronary sinus was incised and continued into the other 2 sinuses. Utilizing a ganglion knife, the Freestyle valve was freed from the native aortic tissue to the proximal suture line. The Dacron sewing ring was then separated using sharp dissection and the lower suture line excised. No calcification was noted in any case. The mean time interval between the first and second operative procedure was 13.4 +/- 21.5 months. There were no operative deaths and only one late death. Mean long-term follow-up was 43 +/- 29 months. Reoperation on a Freestyle stentless aortic valve, when necessary, can be accomplished without increased operative risk and with excellent survival.

Adult↗
PubMed1999

Noninvasive evaluation of hand circulation before radial artery harvest for coronary artery bypass grafting.

OBJECTIVE: Radial artery harvesting for coronary artery bypass may lead to digit ischemia if collateral hand circulation is inadequate. The modified Allen's test is the most common preoperative screening test used. Unfortunately, this test has high false-positive and false-negative rates. The purpose of this study was to compare the results of a modified Allen's test with digit pressure change during radial artery compression for assessing collateral circulation before radial artery harvest. METHODS: One hundred twenty-nine consecutive patients were studied before coronary artery bypass operations. A modified Allen's test was performed with Doppler ultrasound to assess blood flow in the superficial palmar arch before and during radial artery compression. A decreased audible Doppler signal after radial artery compression was considered a positive modified Allen's test. First and second digit pressures were measured before and during radial artery compression. A decrease in digit pressure of 40 mm Hg or more (digit DeltaP) with radial artery compression was considered positive. RESULTS: Seven of 14 dominant extremities (50%) and 8 of the 16 nondominant extremities (50%) with a positive modified Allen's test had a digit DeltaP of less than 40 mm Hg (false positive). Sixteen of 115 dominant extremities (14%) and 5 of 112 nondominant extremities (4%) with a negative Allen's test had a digit DeltaP of 40 mm Hg or more with radial artery compression (false negative). CONCLUSION: Use of the modified Allen's test for screening before radial artery harvest may unnecessarily exclude some patients from use of this conduit and may also place a number of patients at risk for digit ischemia from such harvest. Direct digit pressure measurement is a simple, objective method that may more precisely select patients for radial artery harvest. Additional studies are needed to define objective digital pressure criteria that will accurately predict patients at risk for hand ischemia after radial harvest.

Adult↗
PubMed1998

Preoperative predictors of cost in Medicare-age patients undergoing coronary artery bypass grafting.

BACKGROUND: Identification of preoperative factors that contribute to the cost of coronary artery bypass grafting could aid in predicting the procedure's expense. In this study, 30 sociodemographic and clinical preoperative factors were examined with "survival analysis" techniques to determine characteristics related to total hospital cost. METHODS: Characteristics of all patients age 65 or older undergoing isolated coronary artery bypass grafting from July 1993 to April 1995 (n = 757) were recorded. Software was developed within the hospital's Transitions Systems, Inc, database to calculate the outcome variable of total cost. Nonparametric methods were used for the univariate analysis of the data, and the Cox proportional hazards model was used for the multivariable analysis, censoring 25 patients who died in the hospital. RESULTS: Median hospital cost from the day of the operation until discharge was $15,198. Median length of stay after the operation was 6 days. Multivariable analysis revealed that age, preoperative renal failure, history of cerebrovascular accident, low ejection fraction, and surgical urgency were independent predictors of total cost. CONCLUSIONS: This study, using an accurate representation of true hospital cost and a modeling technique that accounts for the confounding effect of in-hospital death on cost, provides a template for analysis of cost in other patient groups.

Age Factors↗
PubMed1997

The aortic homograft: evolution of indications, techniques, and results in 107 patients.

BACKGROUND: Homograft aortic valve replacement has been performed in 107 patients during the past 7 years. Two primary methods of implantation were used (intraaortic and root replacement). Results of both methods are presented. METHODS: Intraaortic implantation (subcoronary or cylinder technique) was performed in 36 patients (mean age, 54 years) for aortic stenosis or regurgitation (31 patients) and endocarditis (5 patients). Aortic root replacement was performed in 71 patients (mean age, 62 years). The majority (58 patients) had complex root pathologies such as ascending aneurysm, dissection, or prosthetic endocarditis with annular destruction. Early results were assessed with intraoperative or predischarge echocardiography; annual echocardiograms provided long-term follow-up. Left ventricular mass was calculated in patients with long-standing pathology for whom preoperative and postoperative data were available. RESULTS: Early valvular insufficiency was documented in 16 of the 36 intraaortic implants (44%); 9 of these have had progression of the insufficiency. Of the 20 patients who had trivial or no early insufficiency, significant insufficiency has developed in 7 and mild insufficiency has developed in 5. Calculation of left ventricular mass revealed a mean reduction of 11% at 1 year. There has been no mortality, endocarditis, or homograft-related reoperation in the intraaortic group with a mean follow-up of 50 months. The root replacement group had a hospital mortality of 17%. The cardiac pathology was limited to the aortic valve in 12 patients; mortality in this subset was zero. There has been no significant early or late postoperative valvular insufficiency in the 59 surviving patients. More rapid left ventricular mass reduction was seen in this group with a 26% mean reduction within 1 year. A mean follow-up of 32 months in the root replacement group has seen no homograft-related reoperations. CONCLUSIONS: Although the lack of early mortality in the intraaortic group makes this technique appealing, the high incidence of early insufficiency with the realistic expectation of progression has led to our abandonment of the intraaortic technique. Homograft aortic root replacement confers a higher mortality based on the severity of aortic pathology, but offers excellent long-term hemodynamics in any patient. We have expanded our indication for homograft root replacement to include patients with isolated valvular disease rather than reserving it for those patients with extensive root pathology.

Adult↗
PubMed1993

Evolution of aortic valve replacement for native aortic valve endocarditis.

In 1964 and 1965, two groups of surgeons, Dr Thomas Yeh and colleagues from Medical College of Georgia and Dr Andrew Wallace and colleagues from Duke University, published reports of aortic valve exploration, debridement, and replacement for endocarditis. Their initial thoughtful and meticulous procedures initiated valve surgery as a treatment of native aortic valve endocarditis.

Aortic Valve↗
PubMed1993

Early experience with homograft aortic root replacement for complex aortic pathology.

BACKGROUND: Complex aortic valve and root pathology presents a serious operative challenge. METHODS: During the last 45 months 21 cryopreserved homograft root replacements have been performed in 19 patients. The ages of the patients ranged from 28 to 77 years; there were 15 men and four women. Six patients had endocarditis, four prosthetic and two native valve endocarditis. One patient underwent homograft aortic root replacement twice; one underwent concomitant homograft right ventricular outflow tract reconstruction for pulmonic endocarditis. Causes of aortic pathology in the other 13 patients included ascending aortic aneurysm with valvular regurgitation in seven, Marfan syndrome in two, and four aortic dissections with aortic regurgitation. Ten of the nineteen patients were undergoing reoperative procedures. RESULTS: There were three hospital deaths and one death at home of unknown cause. Two of the three patients who died in hospital had undergone redo cardiac procedures. Dramatic functional class improvement was seen in all survivors. CONCLUSIONS: Follow-up from 2 to 45 months in the fifteen survivors revealed no clinical or significant echocardiographic evidence of valvular regurgitation or recurrent infection. We believe homograft root replacement provides an excellent method of reconstruction with several advantages unique to human valved conduits, including ease of handling, lack of synthetic nidus for recurrent infection, and absence of thrombogenic materials. Homografts should be considered the approach of choice in complex valvular and root infectious processes.

Adult↗
PubMed1990

Selective monitoring of patients with suspected blunt cardiac injury.

Blunt chest trauma can result in cardiac injury with consequent dysrhythmias, valve malfunction, or frank rupture. Typically, patients with blunt chest trauma and suspected cardiac injury have required cardiac monitoring for 48 to 72 hours. Predicting which patients with blunt chest trauma are not at risk for cardiac complications would obviate many patient-hours of monitoring in the intensive care unit. This series examines the sensitivity of two-dimensional surface echocardiography in predicting cardiac complications. Over a 24-month period, 115 patients were admitted with blunt chest trauma and prospectively evaluated for cardiac injury with admission electrocardiograms, serial creatine kinase isoenzyme studies, and two-dimensional echocardiography. Thirty-one patients (27%) had abnormal two-dimensional echocardiograms. In 8 (25.8%) of these patients, cardiac complications requiring treatment developed. Eighty-four patients (73%) had normal two-dimensional echocardiograms, and a cardiac complication requiring treatment developed in only 1 (1.2%) of them. Of the 9 patients who required treatment of cardiac complications, 3 had normal admission electrocardiograms and only 1 had elevated levels of the myocardial-specific isoenzymes of creatine kinase. We believe two-dimensional echocardiography is a sensitive test for evaluating cardiac injury resulting from blunt chest trauma and is helpful in selecting those patients who require monitoring in the intensive care unit.

Adult↗
PubMed1988

The effect of verapamil cardioplegia on myocardial ultrastructure.

The calcium channel blocker, verapamil, was evaluated as an adjunct to cold cardioplegia in 16 randomized patients with unstable angina pectoris who received saphenous vein bypass grafts. Myocardial biopsies taken before cardioplegia showed various degrees of ischemic change as assessed by ultrastructural parameters (mitochondrial swelling, matrix clearance, and sarcotubular dilatation). After reperfusion, the majority of the patients had progressive changes of ischemia, with marked mitochondrial and sarcotubular swelling, depletion of glycogen, chromatin clumping, and myofibrillar disruption; amorphous mitochondrial densities were occasionally seen. The ultrastructural changes after cardioplegia were dependent primarily on the extent of preexisting ischemic damage and did not correlate with the use of verapamil. Verapamil did not protect the ischemic myocardium during cold cardioplegia as assessed ultrastructurally.

Biopsy↗
PubMed1986

Cardiac surgery in patients with chronic renal disease.

The combination of chronic renal failure and cardiovascular disease is identified frequently and results in high morbidity and mortality without appropriate medical and surgical therapy. Experience during the last eighteen years has shown that cardiac operations can be undertaken in this high-risk group with acceptable morbidity and mortality and with reasonable expectation of symptomatic improvement. In a six-year period, 17 patients with chronic renal disease underwent cardiac procedures at the Vanderbilt University Affiliated Hospitals. Ten patients were on long-term hemodialysis, and 7 had a functioning renal transplant. Thirteen patients had a coronary artery bypass procedure alone, 1 had a bypass procedure plus aortic valve replacement, 1 had a bypass procedure plus repair of the mitral valve, 1 had a bypass procedure and resection of a left ventricular aneurysm, and 1 had aortic valve and mitral valve replacement for endocarditis. Sixteen patients survived and were discharged. The hospital stay was shorter for patients with a renal transplant than for those on hemodialysis (mean, 11 days versus 22 days, respectively), and perioperative complications were less frequent in the transplant group. There has been 1 late death unrelated to the operative procedure. Fifteen long-term survivors have been followed a mean of 26 months (range 7 to 108 months). All have achieved symptomatic improvement and are in New York Heart Association Functional Class I or II. These results in this high-risk patient group provide a basis for cautious optimism and for a continued aggressive approach in patients with chronic renal disease who require cardiac operation.

Adult↗
PubMed1986

The efficacy and timing of operative intervention for spontaneous pneumothorax.

To reassess the role and timing of operative intervention for spontaneous pneumothorax, 119 patients were retrospectively reviewed to compare recurrences, complications, and hospital stay between a nonoperative group (Group 1) and an operative group (Group 2). Total hospital days were greater in Group 2, but excluding the length of preoperative stay, the number of hospital days were similar in both groups. Group 1 patients more than 40 years old had a longer postoperative hospitalization, but not a higher rate of complication. Overall, morbidity was not different between the two groups, and there were no immediate or perioperative deaths in either group. There were no recurrences in Group 2. At least 11 of the 49 patients in Group 1 had a recurrence (p = .012). Considering the excellent results achieved with operative pleurodesis and the total hospital days accrued with nonoperative therapy, operative pleurodesis should be considered if an active leak persists more than three days after the initial episode of spontaneous pneumothorax or at the time of the first recurrence in the hospitalized patient.

Adolescent↗
PubMed1986

Repair of interrupted aortic arch and associated malformations in infancy: indications for complete or partial repair.

There is uncertainty regarding the best method of repair of interrupted aortic arch. The question is whether to perform primary definitive repair of this anomaly plus the associated defects versus arch repair only and palliation of the intracardiac defects, usually by pulmonary artery banding. Since 1976, 16 infants with interrupted aortic arch have been treated surgically. They were seen at 5.2 +/- 3 days of age and weighed 3.2 +/- 0.7 kg. The interruption occurred between the left carotid and left subclavian arteries (type B) in 9 and between the left subclavian artery and the descending aorta in 7 (type A). Isolated ventricular septal defect (VSD) was the only associated anomaly in 7 and aortopulmonary window, in 4. Two patients had truncus arteriosus type 1. Three had transposition of the great arteries: 1 with VSD and 2 with single ventricle. Prior to 1980, our policy was to palliate all patients. Between 1976 and 1980, 4 infants underwent left thoracotomy with arch repair plus pulmonary artery banding (3, VSD; 7, transposition of the great vessels and single ventricle) with only 1 (25%) survivor. Because of this high mortality, 8 patients with interrupted aortic arch and VSD or aortopulmonary window, seen since 1980, received complete repair with median sternotomy, end-to-end arch anastomosis, and closure of the VSD or aortopulmonary window utilizing profound hypothermia and circulatory arrest. All 8 survived.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗
PubMed1985

The results of valve replacement for mitral valve prolapse.

Between January, 1975, and December, 1982, 33 patients underwent mitral valve replacement for mitral valve prolapse secondary to myxomatous degeneration. The majority were in the seventh decade of life (median age, 62 years), and all were seen with symptoms of mitral regurgitation. Echocardiography was more accurate in making the diagnosis of mitral valve prolapse more often (75%) than angiography (66%). Thirty-eight percent of the patients who underwent cineangiography had concomitant coronary artery disease and had coronary artery bypass grafting as well as mitral valve replacement. There was 1 operative death, an operative mortality of 3%. There were 6 late deaths, a late mortality of 18%. Of the 26 long-term survivors, 23 (88%) were in New York Heart Association Functional Class I and 3 (12%) were in Class II. The average length of follow-up was 33.25 months, and the 5-year actuarial survival was 76%. There was only one incident of thromboembolism (3%). Short-term and long-term survival were not related to the severity of mitral regurgitation but to the status of the left ventricle and the overall condition of the patient. These data suggest that older patients with severe mitral regurgitation secondary to mitral valve prolapse can undergo valve replacement with low operative mortality and gratifying long-term results.

Actuarial Analysis↗
PubMed1984

Perioperative beta blockade with propranolol: reduction in myocardial oxygen demands and incidence of atrial and ventricular arrhythmias.

To determine the effect of beta blockade with propranolol on myocardial oxygen demands and postoperative arrhythmias in patients having coronary bypass operations, 50 patients with chronic stable angina undergoing operation were randomized in a double-blind fashion to receive either propranolol (60 mg every 6 hours) or a placebo. Drug administration began 24 to 48 hours prior to operation and continued through the operative period and for one month after operation. There were no deaths. Two perioperative myocardial infarctions occurred, both in patients receiving a placebo. Myocardial oxygen demand as measured by the rate-pressure product (heart rate X mean arterial pressure) was significantly reduced during induction of anesthesia (7,658 +/- 451 versus 5,786 +/- 340; p less than 0.002) and during sternotomy (8,400 +/- 550 versus 6,756 +/- 384; p less than 0.02) in propranolol-treated patients. In the first two postoperative days, nitroprusside was required for control of hypertension of 10 patients in the placebo group but in only 3 patients given propranolol (p less than 0.05). Postoperatively, 15 of the 26 patients who received a placebo had 45 episodes of arrhythmia. Seven of the 24 propranolol-treated patients had 17 episodes (p less than 0.04). We conclude that propranolol given perioperatively in doses large enough to induce beta blockade significantly reduces myocardial oxygen demands in the vulnerable period during induction of anesthesia and sternotomy, reduces the need for antihypertensive therapy in the immediate postoperative period, and causes a marked reduction in the incidence and frequency of both supraventricular and ventricular arrhythmias in the postoperative period.

Angina Pectoris↗
PubMed1984

The feasibility of adjuvant surgery in limited-stage small cell carcinoma: a prospective evaluation.

Forty patients with limited-stage small cell carcinoma of the lung were prospectively evaluated for adjuvant surgery after intensive chemotherapy to determine resectability. All patients giving informed consent and having a Karnofsky performance status greater than or equal to 50% were included in the study, which ran from May, 1980, to September, 1982. Ages ranged from 40 to 70 years (median, 59 years). One patient was lost to follow-up. Thirty-nine patients were evaluated for operation 9 to 15 weeks after diagnosis and after having received two to four cycles of chemotherapy intravenously every 3 weeks (cyclophosphamide, 1,000 mg/m2; doxorubicin, 50 mg/m2; vincristine, 1 mg/m2; VP-16, 300 mg/m2). Two patients had clinical Stage I tumors; 12 patients, Stage II; and 25 patients, Stage III. At the time of reevaluation there were 13 (33%) complete responders, 21 (54%) partial responders, and 5 (13%) with stable disease. Eleven (28%) of the 39 patients underwent thoracotomy using standard resection criteria for non-small cell carcinoma. Eight of these 11 had resectable lesions (2, Stage I; 3, Stage II; 3, Stage III); five pneumonectomies and three lobectomies were performed. Tumor was present in six of eight specimens. Twenty-eight patients were not candidates for operation for various reasons: poor pulmonary function, 5; unresectable tumors, 10; refusal, 6; very poor medical condition, 6; and primary site not identified, 1. Median survival for complete responders was 17 months and for partial responders, 11 months. We have prospectively identified suitable candidates for adjuvant surgery among the total group (denominator population) of patients with limited-stage small cell carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗