Biomedical subjects

Michael Zacher

Publications and source records attributed to Michael Zacher.

4 recordsLinked to original sources

PubMed2006

Carotid artery cannulation in aortic surgery.

OBJECTIVE: Carotid artery cannulation was initially established at our clinic for surgery of acute aortic dissection, and it became the standard approach for procedures in which circulatory arrest is necessary. The aim of the study was to evaluate this method's efficiency regarding postoperative outcomes after the first 100 procedures. METHODS: Between July 2002 and October 2005, 100 patients underwent aortic surgery using carotid artery cannulation by a side graft for arterial return with a mean flow rate of 4.6 +/- 0.5 L/min. There were 27 patients with acute and 2 with chronic type A aortic dissection. Sixteen patients had had prior cardiac surgery. During circulatory arrest, the arterial line was used for unilateral cerebral perfusion in moderate hypothermia (mean rectal temperature 28 degrees C +/- 1.6 degrees C) with a mean flow rate of 0.85 +/- 0.2 L/min. RESULTS: Carotid artery cannulation offered adequate arterial return in all patients. In no case was a switch to another cannulation site necessary for arterial return. Furthermore, no complications related to the cannulation site were observed. One patient with acute dissection and 1 with chronic aneurysm died during the early postoperative course. Thus, 30-day mortality was 2.0% for the whole group and 3.7% for the dissection group. Two patients with severe calcification of the aortic valve had strokes. There were no strokes in the dissection group, although there were preoperative signs of cerebral malperfusion in 4 patients. CONCLUSIONS: Carotid artery cannulation is a fast, safe, and efficient method of arterial cannulation even in very obese patients. In addition, it simplifies the procedure of unilateral cerebral perfusion through the arterial line during circulatory arrest, making it completely unnecessary to interrupt cerebral perfusion.

Adolescent↗

PubMed2005

Femoral versus aortic cannulation for surgery of chronic ascending aortic aneurysm.

BACKGROUND: Femoral artery cannulation and retrograde arterial perfusion have been postulated to increase the risk of cerebral embolism. In this study, the impact of the arterial cannulation site on the perioperative results after proximal aortic surgery is evaluated. METHODS: Between January 1996 and December 2002, a total of 327 patients underwent proximal aortic repair for chronic non-dissected aortic disease. The arterial inflow was established by cannulation of the aortic arch (group A) or the femoral artery (group F) in 166 and 161 patients, respectively. RESULTS: The early 30-day mortality was 0.9% (3 patients [1 patient in group A and 2 patients in group F]). The overall rate of early focal neurologic dysfunction (permanent and transient) was 4% (13 patients) and there was no significant difference between the two groups (4.2% vs 3.7%). Due to an intraoperative injury of the arterial wall, there were 6 repairs (3.6%) of the aortic arch in group A and 1 repair (0.6%) of the femoral artery in group F. The univariable examination of preoperative and intraoperative variables demonstrated that hypertension and increased cholesterol level could be possible independent risk factors for neurologic morbidity. In the following stepwise logistic regression, only the preoperative hypercholesterolemia was identified as an independent predictor for postoperative focal neurologic dysfunction. CONCLUSIONS: The arterial inflow via the femoral artery and the subsequent retrograde perfusion during cardiopulmonary bypass do not increase the risk of neurologic complications in patients who undergo proximal aortic repair due to chronic non-dissected aortic aneurysm. Because there is an increased risk of aortic wall injury during cannulation, the femoral artery seems to be more suitable in these cases for cannulation than the proximal aorta.

Adult↗

PubMed2003

Valved stentless composite graft: clinical outcomes and hemodynamic characteristics.

BACKGROUND: The valved stentless composite graft has become well established in our hospital for replacement of the ascending aorta and aortic valve in elderly patients and those with contraindication for lifelong anticoagulation. This study was conducted to evaluate the postoperative hemodynamic characteristics and clinical outcomes after implantation of this device. METHODS: Between November 1998 and February 2001, 45 consecutive patients with a mean age of 69 years underwent implantation of a composite graft using a stentless valve prosthesis (Toronto SPV) incorporated in a collagen-coated Dacron tube (InterGard). The indication for surgery was aortic valve disease with an accompanying true aneurysm of the ascending aorta in 42 patients and a dissection of the aortic wall in 3 patients. Postoperative echocardiographic examinations were performed before discharge from the hospital and at the time of the follow-up. Mean follow-up duration was 18 months (range 3 to 30 months). RESULTS: There was no perioperative mortality. During follow-up, there were two noncardiac, nonvalve-related deaths. Echocardiographic evaluation before discharge and at follow-up demonstrated favorable hemodynamics of the valve prosthesis with mean transvalvular gradients of 8.5 +/- 2.9 mmHg and 8.0 +/- 3.1 mmHg, respectively. No regurgitation across the valve and no contact of the cusps with the Dacron tube were seen in any case. CONCLUSIONS: A stentless composite graft for replacement of the aortic valve and ascending aorta offers excellent hemodynamic results and is a suitable device for patients in whom anticoagulation should be avoided.

Adult↗

PubMed2003

Is extended aortic replacement in acute type A dissection justifiable?

BACKGROUND: The aim of this study was to evaluate the effectiveness of our surgical strategy for acute aortic dissection based on the extent of the dissection and the site of the entry, with special emphasis on resection of all dissected aortic segments if technically possible. METHODS: Between January 1995 and March 2001, 43 consecutive patients underwent operations for acute aortic dissection. In all patients the distal repair was performed under circulatory arrest without the use of an aortic cross-clamp. Fifteen patients underwent aortic arch replacement with additional reconstruction of supra-aortic vessels in 3 patients. Complete replacement of all dissected tissue could be achieved in 21 patients (group 1). Because of the distal extent of the dissection beyond the aortic arch, replacement of all the dissected tissue was not possible in 22 patients (group 2). RESULTS: Early mortality was 4.7% (2 patients), and the incidence of perioperative cerebrovascular events was 7.0% (3 patients). All of these events occurred in group 2 (p < 0.025). During the follow-up period of 6 years or less, 5 patients died, all from causes not related to the aorta or the aortic valve. A persisting patent false lumen was observed in 14 of the 36 surviving patients (39%). CONCLUSIONS: Extended replacement of the dissected ascending aorta and aortic arch can be done with good early and midterm results, even though it requires a complex surgical technique. Therefore we advocate complete replacement of the dissected parts of the aorta in all patients in whom this is technically possible.

Aged↗