Biomedical subjects

R B Griepp

Publications and source records attributed to R B Griepp.

202 records · Page 12Linked to original sources

PubMedDate not supplied

The Bentall procedure in patients with Marfan's syndrome.

From 1985 to 1996, 18 patients with Marfan's syndrome underwent the Bentall procedure at Mount Sinai Hospital. They are compared with 38 patients aged < 40 without Marfan's syndrome who also underwent composite valve-graft replacement of the ascending aorta. The mean age of the non-Marfan group was 33 while that of the Marfan group was 29. Nearly three-quarters of each group were male. Aortic dissection was present in 33% of the Marfan group but only in 18% of the other group. Seventy-eight percent of the Marfan patients and 89% of the non-Marfan patients had aortic regurgitation. Twenty-one percent of the patients in the control group nevertheless had gross aortic pathology suggestive of Marfan's syndrome and may have had variants of the syndrome; 26% of the non-Marfan group had a bicuspid aortic valve. A modification of the Bentall procedure with implantation of coronary artery buttons was performed in the majority of the patients in both groups. Three patients, all in the group with Marfan's syndrome, required a concomitant mitral valve procedure. There was one death in each group. Two non-Marfan patients required reoperation; neither had dissection. Four patients with Marfan's syndrome underwent reoperation for distal disease in the aorta; they comprised one third of the Marfan patients who had aortic dissection. Three late complications occurred in the group with Marfan's syndrome: progressive cardiomyopathy; myocardial infarction; and late tamponade. There were also two late sudden deaths in the group with Marfan's syndrome, which may have been the consequence of aortic rupture. No difference in immediate operative mortality following the Bentall procedure was noted between patients with and without Marfan's syndrome, but young patients without Marfan's syndrome seem to have better event-free and long-term survival. In patients with Marfan's syndrome, the presence of acute dissection makes reoperation more likely, and sudden death from rupture still occurs despite careful postoperative surveillance. A higher incidence of severe mitral valve disease was found among young patients with Marfan syndrome than in controls.

Adolescent↗

PubMedDate not supplied

Hemostasis in aortic and cardiothoracic surgery.

Hemostasis abnormalities in cardiovascular and aortic surgery remain a major source of morbidity and mortality in patients undergoing such complex procedures. The need for frequent transfusions of red cell and other blood products increases risks and costs to patients and institutions providing patient care. Specifically in cardiovascular and aortic surgery, the nature of the surgery is, at best, semi-elective, and careful preparation to preserve the hemostatic mechanisms of the body is essential. Contact of blood with the extracorporeal circuit induces a hemorrhagic diathesis through a variety of different mechanisms. Dilution of the patient's blood volume by the extracorporeal circuit prime causes depletion of platelets and coagulation factor levels. Aorto intimal disease initiates fibrinolysis by the release of tissue plasminogen activator. Due to the numerous etiologies of bleeding, a combination of blood conservation strategies is suggested. The ideal combination of interventions has yet to be determined and is currently dependent on patient variables, physician and institutional practices, and economic pressures.

Aminocaproic Acid↗

PubMedDate not supplied

Identification of risk factors in patients undergoing thoracoabdominal aneurysm repair.

Developments and advances in surgical and anesthetic techniques have lead to increased survival in patients undergoing complex thoracic aortic aneurysm repairs. The decision to operate, however, continues to be based in a large degree on the clinical impression of the patient's ability to withstand the rigors of the procedure. As part of the ongoing effort of our department to further elucidate those parameters that impart added risk to patients, the diameters and volumes of CT-imaged aortas were determined for 67 surgical and nonoperatively managed patients. Significant differences were found between those patients not requiring surgery, and both those undergoing operation and those that died of rupture. Similarly, the average yearly increase in volume in surgical and rupture patients was higher than that of nonoperatively managed patients. Those patients who smoked also were found to have a significant yearly increase in size of their aortas relative to those patents that did not. An algorithm for managing patients presenting with thoracoabdominal aneurysms based upon size at initial presentation, change in annual diameter and volume, and estimated risk for paraplegia is presented.

Adult↗

PubMedDate not supplied

Use of hypothermic circulatory arrest for cerebral protection during aortic surgery.

Optimal use of hypothermic circulatory arrest during aortic surgery requires understanding of its physiology. Research in laboratory animals and clinical observations have now documented that considerable residual cerebral metabolism remains with cooling to levels of 15-18 degrees C, especially if cooling intervals are short, reflected by persistent jugular venous desaturation. Cooling should be continued to below 15 degrees C if the duration of HCA is expected to exceed 20 minutes, and continued until jugular venous saturations exceed 95%. There is considerable laboratory evidence that even short durations of HCA are followed by a prolonged interval of increased cerebral vascular resistance during which cerebral metabolism is maintained at normal levels by markedly increased oxygen extraction. Clinical observations have now confirmed that considerable jugular venous desaturation is present in patients following HCA: it is more pronounced with prolonged HCA, and is still present as late as six hours after the start of rewarming. This reinforces the concept of a prolonged postoperative vulnerable interval following HCA, during which any compromise in oxygen delivery has the potential for producing cerebral injury. Several adjunctive measures have been shown to improve outcome following HCA. The simplest and most important is topical hypothermia: packing the head in ice during the interval of HCA. Retrograde cerebral perfusion (RCP) has also been shown to improve EEG recovery as well as histological and behavioral outcome in laboratory animals following prolonged HCA, but some of its effect may be secondary to its efficacy in keeping the brain cold, since RCP provides very low rates of flow and supports metabolism at a much lower level than antegrade perfusion at the same temperature. But despite the clear superiority of antegrade perfusion, and the documentation of some benefits of RCP in laboratory measures of cerebral protection, clinical results using RCP and ACP have not yet demonstrated the superiority of these methods over use of HCA alone, perhaps because these modalities are usually employed in patients with unusually high risk of neurological injury: those with dissection or with clot or atheroma in the aorta. Nevertheless, recent years have seen considerable reduction in mortality following aortic surgery, especially in older patients, and a trend toward a lower incidence of permanent neurologic dysfunction. The presence of preoperative rupture or hemodynamic compromise, and of clot or atheroma in the aorta, remain the most significant risk factors both for death and occurrence of stroke.

Animals↗