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Biomedical subjects

R B Griepp

Publications and source records attributed to R B Griepp.

At least 127 records · Page 7Linked to original sources
PubMed1979

Operative treatment of aortic dissections. Experience with 125 patients over a sixteen-year period.

An unselected, consecutive cohort of 125 patients underwent operative repair of acute and chronic aortic dissections with tubular graft interposition over a 16 year span. The absence of remote geographical referral biases and the unselected nature of this series provided a patient population that was representative of the disease process (as assessed heretofore only from autopsy series). Furthermore, this enabled high-risk subsets to be defined by retrospective analysis. Patients were classified according to whether the ascending aorta was involved (type A with involvement, type B without), irrespective of the site of intimal tear, and according to age of the dissection: Fifty-three patients had acute type A (Ac-A), 29 had chronic type A (Ch-A), 20 had acute type B (Ac-B), and 23 had chronic type B (Ch-B) dissections. Fourteen percent (17/125) of the dissections had ruptured. Concomitant aortic valve replacement (AVR) was performed in 11% (6/53) for Ac-A cases and 38% (11/29) of the Ch-A cases. A total of 391 patient-years of follow-up was analyzed; follow-up averaged 4.5 years and extended to 13.7 years. Over-all operative mortality rate was 34% (18/53) for Ac-A, 14% (4/29) for Ch-A, 45% (9/20) for Ac-B, and 22% (5/23) for Ch-B; during the most recent 5 year interval these figures were lower: 27%, 8%, 20%, and 20%, respectively, N = 50. Multiple preoperative variables were found to correlate significantly with both operative death and long-term survival. Operative survivors generally experienced satisfactory functional benefit. Late attrition averaged 8% per year; 61% of all late deaths were related to cardiac or cerebral causes. Over-all actuarial survival (+/- SEM) for the entire cohort was 54% +/- 5% at 5 years and 26% +/- 7% at 10 years; for the 89 patients surviving operation, these figures were 76% +/- 5% and 37% +/- 10%, respectively. No significant differences in long-term survival were evident between the different subgroups. Whether the primary intimal tear had been resected or concomitant AVR had been performed had no statistically significant bearing on operative mortality, functional result, necessity for late reoperation, or late attrition. The long-term "natural" history of surgically treated patients with aortic dissections, as defined in this study, should facilitate comparison with other treatment modalities. Results of the present analysis support immediate operative intervention for patients with Ac-A dissections and probably for those with Ac-B dissections. Additionally, surgical treatment of patients with symptomatic or enlarging Ch-A and Ch-B dissections provides satisfactory rehabilitation and long-term survival. Finally, we re-emphasize our recommendation for simplified classification of aortic dissections, based solely upon the presence or absence of ascending aortic involvement. Pathophysiology and expected biologic behavior pivot on this feature, and appropriate clinical strategy can thereby be defined.

Adult↗
PubMed1978

A modern view of the surgical treatment of peripheral arterial disease.

As life expectancy increases, more patients will harbor atherosclerotic conditions that portend disability and death. Due basically to a communication gap, sizable numbers of these patients who stand to benefit from vascular reconstruction are not being referred or are being referred too late to vascular surgeons. Vascular surgery currently can save limbs, extend productivity and life expectancy, ameliorate hypertension, and prevent stroke more reliably and with less risk than ever before. As the subspeciality of vascular surgery has matured, has incorporated additional fellowship training, and now approaches potential recognition in some yet to be determined form by The American Board of Surgery, it is incumbent on general physicians and vascular surgeons alike to develop appropriate channels that can transmit clinical concepts, educational information, and clinical results, as well as refer patients.

Abdomen↗
PubMed1978

Tissue valve replacement of prosthetic heart valves for thromboembolism.

Twenty-five patients who had repeated thromboemboli from a prosthetic mitral valve were treated with reoperation using a tissue valve prosthesis. Reoperation was performed an average of 4.0 years after the original valve replacement in 14 men and 11 women, with an average age of 50 (range 35 to 65) years. A stented allograft was used in the first 7 patients and a porcine xenograft in the last 18 patients. There were one hospital death and two late deaths. With the first prosthetic valve there were 66 documented embolic episodes in 101.5 patient years (0.65 embolus/year). Only four embolic episodes in 67.4 patient years (0.059 embolus/year) occurred after tissue valve replacement (P less than 0.001). These results indicate that in patients with recurrent or severe embolization after prosthetic heart valve replacement, rereplacement with a tissue prosthesis can be safely performed and significantly reduces the likelihood that additional embolic episodes will occur.

Adult↗
PubMed1978

Alterations in total and regional myocardial blood flow during acute rejection of orthotopic canine cardiac allografts.

Using radioactive microspheres, we studied the quantitative and sequential distribution of myocardial blood flow during acute rejection of cardiac orthotopic allografts in 15 nonimmunosuppressed dogs. During rejection mean cardiac output per kilogram decreased 49 percent from control, stroke volume per kilogram decreased 40 percent, total left ventricular flow decreased 43 percent, and the subendocardial/subepicardial flow ratio (I/O) of the left ventricular free wall decreased 21 percent. Relative subendocardial hypoperfusion occurred despite an increase in the ratio of left ventricle subendocardial supply (diastolic pressure-time index) to demand (tension-time index). The data indicate that total left ventricular flow decreases severely and selective left ventricular subendocardial ischemia develops very early during acute cardiac rejection.

Animals↗
PubMed1977

Coronary arterial narrowing in Takayasu's aortitis.

A patient with Takayasu's aortitis and angina pectoris due to severe narrowing of the right and left coronary arterial ostia is described. Takayasu's arteritis produces a panaortitis, with thickening of the adventitia predominating, and an inflammatory cell infiltrate involving the adventitia, outer media and vasa vasorum. Narrowing of the coronary arteries in this disease is due to extension into these arteries of the processes of proliferation of the intima and contraction of the fibrotic media and adventitia that occur in the aorta. The distal coronary arteries usually do not manifest arteritis and are normal in caliber. Angina pectoris may be the first symptom of the disease if the coronary arteries are the initial site of severe arterial narrowing. The coronary arterial bypass graft operation is effective therapy for treating coronary arterial narrowing due to Takayasu's arteritis.

Adult↗
PubMed1977

Isolated aortic valve replacement in patients older than 65 years.

The results of 196 isolated aortic valve replacements in patients older than 65 years were analyzed. Eighty-four percent of patients were in New York Heart Association (NYHA) functional class III or IV preoperatively. The operative mortality was 12% for all cases and 9% for elective cases. Actuarial probability of five-year survival was 55% for the entire group and 61% for discharged patients. Myocardial failure and congestive heart failure were the most common causes of early and late postoperative death, respectively. Embolic strokes occurred in 16% of discharged patients and caused substantial disability in 9%. At the termination of the study, 94% of surviving patients were in NYHA class I or II, and none were in class IV. Aortic valve replacement in elderly patients entails reasonable operative risk, and results in satisfactory postoperative rehabilitation.

Age Factors↗
PubMed1977

Patient-related risk factors as predictors of results following isolated mitral valve replacement.

Results following isolated mitral valve replacement in 897 consecutive patients over a twelve-year period were analyzed with regard to the influence of various preoperative patient-related risk factors. Actuarial data analysis allowed definition of major preoperative, etiological, clinical, and hemodynamic correlates to both perioperative and long-term postoperative patient survival. Patient age below 60 years, preoperative New York Heart Association Functional Class of III or less, cardiac index greater than 2.0, and left ventricular end-diastolic pressure of less than 12 mm Hg were all highly significant correlates of improved perioperative as well as long-term patient survival. Patients whose predominant functional lesion was mitral insufficiency had only a 53% five-year survival (187 of 352 patients) following mitral valve replacement as opposed to 70% (521 of 745 patients) for those who had mixed or stenotic mitral lesions. Primary ischemic mitral dysfunction was associated with only 31% five-year survival (17 of 54 patients) after mitral valve replacement in contrast to 69% (480 of 695 patients) for patients with rheumatic mitral lesions. The presence of occlusive coronary artery disease coexisting with, but not the primary cause of, mitral dysfunction was associated with decreased perioperative and late postoperative survival. Results support both earlier operative intervention and wider use of associated procedures, ie, coronary bypass grafting, with mitral valve replacement. Recognition of major preoperative patient-related risk factors should enhance survival following this procedure.

Adult↗
PubMed1977

Valve replacement with the Starr-Edwards and Hancock prostheses: comparative analysis of late morbidity and mortality.

Although the Starr-Edwards caged-ball valve remains a standard of comparison for more recently introduced prostheses, a substantial incidence of thromboembolic and hemorrhagic complications prompted our evaluation of the Hancock glutaraldehyde-fixed porcine xenograft. We have compared the results of 435 aortic valve replacements using the Starr- Edwards valve (SE-AVR), 515 mitral valve replacements (SE-MVR), and 121 double-valve replacements (SE-AVRMVR) with 251 aortic valve replacements using the xenograft aortic valve (X-AVR), 338 mitral valve replacements (X-MVR), and 88 double-valve replacements (X-AVR-MVR). The Starr- Edwards valves were used during the period 1963 through 1973 and the xenograft valves between 1971 and 1976. No significant differences in patient age, sex, or preoperative hemodynamic data were noted between comparable groups. All patients with Starr-Edwards valves received long-term anticoagulation while anticoagulants were used only for specific indications in patients with xenograft valves. Total follow up was 3944 patient years for the Starr-Edwards patients and 947 patient years for the xenograft patients. Hospital mortality was not significantly different for comparable groups: SE-AVR 6.9% vs. X-AVR 6.4%, SE-MVR 9.7% vs X-MVR 8.6%, and SE-AVR-MVR 7.5% vs. X-AVR-MVR 10.2%. Linearized mortality and morbidity data expressed as percent per patient- year are tabulated below. Pairs which differ significantly (p < .05) are italicized.

Animals↗
PubMed1977

Adenosine triphosphatase located on unstimulated human small lymphocyte cell membranes.

This study was undertaken to localize the enzyme sodium-potassium dependent adenosine triphosphatase in unstimulated human small lymphocytes using the histochemical technique of McClurkin [1964]. The substrate adenosine 5' triphosphate is hydrolyzed by the ATPase resulting in a lead phosphate precipitate at the site of enzyme action, subsequently visualized as lead sulphide. The enzyme was demonstrated in three different patterns, and for each donor the pattern was constant both on all four of the test slides, and on different occasions. The patterns observed were: clusters of granules related to the cell membrane; positive staining localized to portions of the cell membrane, and, less commonly, the whole cell circumference. The significance of this distribution may relate to areas with large numbers of antigen recognition sites on the lymphocyte membrane.

Adenosine Triphosphatases↗
PubMed1977

Surgical correction of types II and III truncus arteriosus.

In truncus arteriosus types II and III, one or both pulmonary arteries arise independently from either side of the truncus. In the surgical correction of this anomaly, we have utilized on operative technique in which the essential features are as follows: ventricular septal defect (VSD) closure, which directs left ventricular outflow into the truncus: (2) anastomosis of a Dacron tube containing a glutaraldehyde-preserved procine aortic heterograft to the right ventriculotomy: (3) removal of a circumferential band of the truncus containing both pulmonary artery orifices; (4) tailoring of the band of truncus tissue into a generous cuff which is anastomosed to the distal end of the valved Dacron conduit; and (5) restoration of aortic continuity with a tubular Dacron graft. Since 1971, 4 children ages 2 to 9 years have undergone successful correction of truncus arteriosus types II or III by this technique. In one patient with marked pulmonary hypertension and congestive heart failure preoperatively, the pulmonary vascular resistance had reverted to normal by 3 years after the operation. In one patient in whom bronchial collaterals to the right pulmonary artery were present, postoperative left ventricular failure required reoperation for ligation of the collaterals. All 4 patients are asymptomatic and fully active 5 to 60 months postoperatively. None has evidence of stenosis or insufficiency of the heterograft valve.

Animals↗
PubMed1977

Control of myocardial performance early after open-heart operations by vasodilator treatment.

The hemodynamic effects of vasodilator treatment (afterload reduction) with nitroprusside at a constant heart rate were studied in 24 patients early after aorta-coronary bypass grafting. In 12 patients, dose-response relationships were determined. Graded incremental infusions of nitroprusside produced progressive decreases in mean arterial pressure (MAP), right and left atrial pressures, and stroke work index. Stroke volume index and cardiac index rose significantly until MAP was reduced below the range of 80 to 90 mm. Hg, and then they fell to base-line levels owing to insufficient preload. In an additional 12 patients, MAP was reduced with nitroprusside to the range of 80 to 90 mm. Hg, and left atrial pressure was then restored to base-line levels during continued vasodilator administration. This sequence resulted in further augmentation of stroke volume index to a level higher than that produced by nitroprusside alone. We conclude from this investigation that nitroprusside is a clinically useful agent for primary or adjunctive therapy of mild-to-moderate low cardiac output states immediate postoperatively and that simultaneous regulation of left ventricular preload and after load during its administration is necessary in order to achieve maximal hemodynamic benefit.

Blood Pressure↗
PubMed1977

Successful retransplantation of the human heart.

Cardiac retransplantation has been performed in five patients at Stanford University Medical Center. Long-term survival and rehabilitation have been achieved in two cases. In the first case retransplantation was performed 57 days after the initial procedure because of persistent acute graft rejection. The second patient underwent retransplantation 27 months postoperatively because of documented accelerated graft atherosclerosis. The major indications for cardiac retransplantation consist of intractable acute rejection and late postoperative graft atherosclerosis. These complications should prompt consideration of cardiac retransplantation in carefully selected cases.

Adolescent↗