Göran Rådberg

Endovascular Treatment of Type B Thoracic Aortic Dissections

Abstract  Purpose: To evaluate the initial experience of endovascular repair of aortic dissections from a single center. Materials and Methods: From June 1999 to March 2002, endovascular stent grafting was performed in 20 high‐risk patients (16 to 80 years). Eighteen patients had a type B dissection (14 acute and 4 chronic). Two patients had chronic type A dissection. Preoperative work‐up included CT and MRI to evaluate the extent of the dissection, the relation to the left subclavian artery, the size of false and true lumen, and branch complications. Results: Stent‐graft deployment was technically successful in all cases. None was converted to open repair. Three patients died within 30 days, i.e., a 15% mortality rate. Four patients (20%) had a perioperative stroke. Paraplegia was observed in one case. No migration of the stent grafts or endoleaks was observed during the mean follow‐up period of 13 months. In all but two patient thrombosis of the false lumen was noted. Conclusions: Endovascular treatment of thoracic dissections is feasible. Early results are encouraging. While endovascular repair with stent‐grafts is progressing rapidly as a viable strategy for aortic dissections in selected patients careful investigations must continue to focus on its safety. Randomized controlled trials are urgently needed. (J Card Surg 2003;18:539‐544)

Treatment of descending thoracic aneurysms by endovascular stent grafting.

Abstract  Purpose: Endovascular stent‐graft treatment for true aneurysms of the descending thoracic aorta is a valid and effective alternative to conventional surgery. A review of our experience with 21 consecutive patients is reported and technical considerations are discussed. Methods: Twenty‐one patients (mean age 73 years) with true aneurysms of the descending thoracic aorta (n = 14) or contained rupture (n = 7) were treated between October 1999 and July 2001. Seven patients (33%) underwent emergency endovascular procedure. Postoperatively, the patients were followed with CT scans at 1, 3, 6, and 12 months. Follow‐up, which averaged 17 months, was 100% complete. Thirty‐day results: No conversions to open repair were necessary. Two patients died (10%), one of acute intestinal ischemia and the other because of multiorgan failure. Four patients showed endoleaks immediately after stenting. Two patients required new endovascular stentgrafts, while the remaining two were treated conservatively. Besides endoleaks, eight major complications occurred in six patients (two stroke, two paraplegia, two respiratory insufficiency, and one renal failure). Mid‐term results: Three more patients died during the follow‐up period. One patient died of heart failure after a complicated postoperative course, 91 days after stenting. The second patient died because of aortic rupture, 139 days after stenting. The third patient died of heart failure, 15 months after the endovascular procedure. The remaining 16 patients are alive and have been regularly controlled by CT scans. No late migration or endoleaks have been detected. In all the survivors, the size of the aneurysm was unchanged or diminished. Conclusions: Treatment of descending thoracic aortic aneurysms by endovascular stentgraft devices has good early and mid‐term results. More accurate selection of patients may further reduce mortality and morbidity.

Effect of reduced aprotinin dosage on blood loss and use of blood products in patients undergoing cardiopulmonary bypass.

High-dose aprotinin reduces bleeding after cardiac surgery, but has also evoked concern with regard to potential side effects and hospital costs. To evaluate the effects of reduced-dose aprotinin on blood loss and need for blood transfusion, 40 patients undergoing myocardial revascularization were studied (double-blind, placebo-controlled). Postoperative bleeding was reduced by 40% and erythrocyte infusion by 85% in the group given 3 x 10(6) KIU aprotinin (1 x 10(6) as a loading dose before cardiopulmonary bypass, 1 x 10(6) in the priming volume and 2.5 x 10(5)/hour intraoperatively) Aprotinin concentrations during the operation were monitored and maintained above the required level. There were no adverse effects of the drug. Hospital expenditure on blood products was reduced by 51% when aprotinin was used. Our study suggests that aprotinin in reduced dosage diminishes bleeding and requirements for blood products, and that it should be given before, during and after cardiopulmonary bypass.

Intraoperative Assessement of Coronary Flow and Coronary Vascular Resistance During Coronary Bypass Surgery

The measurement of coronary graft flow rates is a well-established method of assessing graft function intraoperatively. In order further to understand the dynamics of graft function, the resistance to the flow was considered a desirable measurement intraoperatively. The coronary vascular resistance (CVR) was estimated by applying the Poiseuille-Hagen equation. The CVR was estimated at zero cardiac work (during cardioplegic arrest) using fixed perfusion flow rates and estimating the pressures produced. After going off cardiopulmonary bypass (CPB), the bypass graft flow (F) was estimated by a standard ultrasound Doppler technique. The perfusion pressure over the perfused coronary graft was then determined and the CVR in the working heart ascertained. The CVR was studied in 178 vein grafts in 59 patients undergoing coronary bypass surgery. The mean CVR in the cardioplegic heart (c-CVR) varied from 0.81 to 2.3 mmHg/ml/min for various coronary artery diameters and was significantly higher in small diameter arteries compared with larger arteries (p < 0.0002). Consequently significant high flows were found in the large vessels compared with the smaller ones (p < 0.0001). The mean c-CVR during cardioplegia of 1.57 +/- 0.06 increased significantly to 1.75 +/- 0.07 mmHg/ml/min after the procedure (p-CVR) and was attributed to the dynamic resistance of the working heart. The post-CPB graft flow was significantly and negatively correlated to the c-CVR of the arrested heart. The measurement of coronary vascular resistance reveals coronary beds at potential high risk for inadequate perfusion. Such areas are usually fed by small vessels with low flows. The working heart, in turn, increases the coronary resistance following cardioplegia during the surgical procedure.

Off-pump Bypass Surgery: Experience of 250 Cases

From April 1996 to October 1998, 250 patients with a mean age of 63 years (31-86 years) underwent coronary artery bypass grafting using the off-pump technique. The prime reason for using this technique was the need to minimize the surgical trauma by avoiding extracorporeal circulation. Fifty-seven percent of the patients had 1-vessel disease, 39% had 2-vessel disease and 4% 3-vessel disease. Sternotomy was performed in 196 patients and an anterior mini-thoracotomy in 54 patients. The mean number of coronary anastomoses was 1.5. Perioperative mortality was 0.4%. The first consecutive 87 patients underwent an early postoperative coronary angiography (days 1-5) revealing a graft patency of 96.5%. Five out of the 7 patients with occluded grafts subsequently underwent another intervention (surgical revascularization in 4 patients and percutaneous transluminal coronary angioplasty in one); 1.2% developed transmural myocardial infarction and 2.8% were reoperated upon for bleeding. The mean time of ventilatory support was 2.5+/-0.5 h. The mean ICU time for all patients was 12 h (0-10 days). The mean in-hospital time was 7 days (2-30 days). Coronary artery bypass surgery without the use of extracorporeal circulation is a safe procedure that can be performed with limited need for intensive care resources. However, long-term results remain to be investigated.From April 1996 to October 1998, 250 patients with a mean age of 63 years (31±86 years) underwent coronary artery bypass grafting using the off-pump technique. The prime reason for using this technique was the need to minimize the surgical trauma by avoiding extracorporeal circulation. Fifty-seven percent of the patients had 1-vessel disease, 39% had 2-vessel disease and 4% 3-vessel disease. Sternotomy was performed in 196 patients and an anterior mini-thoracotomy in 54 patients. The mean number of coronary anastomoses was 1.5. Perioperative mortality was 0.4%. The ®rst consecutive 87 patients underwent an early postoperative coronary angiography (days 1±5) revealing a graft patency of 96.5%. Five out of the 7 patients with occluded grafts subsequently underwent another intervention (surgical revascularization in 4 patients and percutaneous transluminal coronary angioplasty in one); 1.2% developed transmural myocardial infarction and 2.8% were reoperated upon for bleeding. The mean time of ventilatory support was 2.5 0.5 h. The mean ICU time for all patients was 12 h (0±10 days). The mean in-hospital time was 7 days (2±30 days). Coronary artery bypass surgery without the use of extracorporeal circulation is a safe procedure that can be performed with limited need for intensive care resources. However, long-term results remain to be investigated.

Gamma globulin prophylaxis to reduce post-transfusion non-A, non-B hepatitis after cardiac surgery with cardiopulmonary bypass.

A prospective, randomized study of immune serum globulin (ISG) for prevention of post-transfusion hepatitis was performed on 196 patients (100 controls without gammaglobulin or placebo and 96 who received ISG) undergoing valve replacement or coronary artery bypass with extracorporeal circulation. The dose of ISG was 2 ml i.m. at premedication and 2 ml i.m. on postoperative day 3. Probable non-A, non-B hepatitis developed postoperatively in ten of the 100 controls and two of the 96 in the ISG group. Two ISG patients and three controls with non-A, non-B hepatitis still have increased serum aminotransferase values after 3-5 years, but liver biopsy revealed hepatitis, which histologically was very mild, in only two control and two ISG patients. Low-dose gamma globulin thus reduced the incidence of acute, probable non-A, non-B hepatitis in cardiac surgery with cardiopulmonary bypass.

Management of Extensive Lesions of the Aortic Arch: Review of 42 Consecutive Cases

This retrospective study reviews the long-term results in aortic arch surgery. Forty-two consecutive patients (44-74 years) were operated on between 1980 and 1995. Nineteen patients had acute dissections of the aortic arch, 11 had chronic dissections and 12 had aneurysms. Twenty patients were given emergency surgery and 22 were operated on electively. Reconstruction of the aortic arch alone (31%) or with other aortic segments (69%) was performed during antegrade cerebral perfusion (81%) or circulatory arrest (17%). Sixteen patients died during the first 30 days (38%). Early mortality rates were 60% in emergencies and 18% in elective cases. Early mortality in the group with aneurysms was 33% and 40% in patients in the dissection group. Long-term follow-up to July 1998 is now complete. Twelve patients (28%) died during the follow-up period; 4 of these deaths were due to a rupture of the descending aorta. Three patients (11.5%) underwent late reoperations on the remaining aorta, without operative mortality. We recommend careful follow-up of patients with aortic arch disease and, when indicated, surgery to avoid the rupture of the remaining aorta.This retrospective study reviews the long-term results in aortic arch surgery. Forty-two consecutive patients (44-74 years) were operated on between 1980 and 1995. Nineteen patients had acute dissections of the aortic arch, 11 had chronic dissections and 12 had aneurysms. Twenty patients were given emergency surgery and 22 were operated on electively. Reconstruction of the aortic arch alone (31%) or with other aortic segments (69%) was performed during antegrade cerebral perfusion (81%) or circulatory arrest (17%). Sixteen patients died during the first 30 days (38%). Early mortality rates were 60% in emergencies and 18% in elective cases. Early mortality in the group with aneurysms was 33% and 40% in patients in the dissection group. Long-term follow-up to July 1998 is now complete. Twelve patients (28%) died during the follow-up period; 4 of these deaths were due to a rupture of the descending aorta. Three patients (11.5%) underwent late reoperations on the remaining aorta, without operative mortality. We recommend careful follow-up of patients with aortic arch disease and, when indicated, surgery to avoid the rupture of the remaining aorta.

Half-dose aprotinin does not affect haemorheological properties in patients undergoing bypass surgery.

ObjectiveTo investigate haemorheological changes in patients undergoing coronary artery bypass grafting and to determine whether the protective effect on haemorheology of high-dose aprotinin also exists under a half-dose regimen. MethodsForty patients were studied in a double-blind, placebo-controlled study design. Patients in the aprotinin group received half of the standard high dose of aprotinin during surgery. Erythrocyte and white-cell clogging rates as well as whole blood and plasma viscosity were measured. Viscosity results were expressed as a ratio to the viscosity of saline. ResultsErythrocyte and white-cell clogging rates were increased significantly, whereas whole blood and plasma viscosity were decreased significantly during cardiopulmonary bypass. The reduction in viscosity had a strong correlation to haemodilution. There was no significant difference in any of the measured variables between the aprotinin and the placebo groups. ConclusionThis study showed that blood cell damage occurred during cardiopulmonary bypass surgery, as measured by a raised clogging rate. This tendency was the same in both groups and therefore no increased potential for microthrombi could be attributed to aprotinin haemorheologically. However, half-dose aprotinin did not show any preserving effect in haemorheology when the blood-cell clogging rate and blood viscosity were studied.

Influence of alprostadil on pulmonary dysfunction after a cardiac operation

To test the effects of alprostadil on pulmonary dysfunction after cardiac operations, we studied 24 male patients undergoing aortocoronary bypass. Twelve were given an intravenous infusion of alprostadil (synthetic prostaglandin E1), 20 ng.kg-1.min-1, in a double-blind manner during operation; the other 12 were controls. Duration of artificial respirator use and frequent blood gas analyses were used to assess postoperative pulmonary function. Use of the artificial respirator postoperatively was significantly lower in the prostaglandin group (mean time. 5.25 +/- 1.81 hours) compared with the controls (mean time, 8.34 +/- 4.35 hours) (p = 0.047). The proportion of patients with hypercapnia and with hypoxia determined every 4 hours for the first 24 hours after extubation was significantly lower in the prostaglandin group compared with the controls (p less than 0.0001). These results indicate that synthetic prostaglandin E1 may play a role in protecting lung tissue during extracorporeal circulation.