Michael Brandt

Severe obesity does not adversely affect perioperative mortality and morbidity in coronary artery bypass surgery.

OBJECTIVE Obese patients are usually thought to have an increased risk for complications in coronary artery bypass surgery. METHODS Therefore, the data of 500 consecutive patients undergoing coronary artery bypass grafting at our department in 1998 by use of cardiopulmonary bypass were analyzed. Severe obesity was defined as body mass index (BMI) > or = 30.0 kg/m(2). Obese patients (n=100; group O) were compared to the remaining 400 patients (group C). Both groups were comparable with respect to sex, history of prior myocardial infarction, chronic obstructive pulmonary disease, previous stroke, duration of cardiopulmonary bypass, aortic cross-clamp time and number of distal anastomoses performed. Obese patients were slightly younger and diabetes and hypertension were more common in these patients. RESULTS Survival and potential complications including perioperative myocardial infarction, sternal wound infection, wound infection at the leg, renal failure, stroke, prolonged mechanical ventilation, pneumonia, reexploration for bleeding, and atrial arrhythmias were analyzed. No significant differences between obese and non-obese patients were detected. CONCLUSION Severe obesity does not necessarily adversely affect perioperative mortality and morbidity in patients undergoing coronary artery bypass grafting in this study.

Stent-Graft Repair versus Open Surgery for the Descending Aorta: A Case-Control Study

Purpose: To compare the clinical outcomes of open surgery versus endovascular repair in patients with pathologies of the descending thoracic aorta (DTA). Methods: This retrospective study included 44 patients (28 men; mean age 68±12 years, range 37–86) treated for DTA pathologies between 1995 and 2003. Twenty-two patients (15 men; mean age 68±13 years, range 37–86) undergoing stent-graft implantation were matched for sex, age, emergency operation, and comorbidities (coronary artery disease, chronic obstructive pulmonary disease) with a 22-patient contemporaneous surgical cohort (13 men; mean age 69±11 years, range 41–80). Results: Thirty-day mortality was 5% in the stent-graft group and 27% in the open surgery group (p=0.047). The incidences of postoperative stroke and paraplegia were both 5% in the stent-graft group and 9%, respectively, in the open surgery cohort. One patient required a second stent-graft due to an endoleak during the same hospital stay, and 2 reoperations were performed in the standard operation group (p = NS). Lengths of stay in the intensive care unit (ICU) and hospital were 4.3±5.4 and 11.9±15.0 days, respectively, in the stent-graft group and 10.0±7.4 and 21.5±17.4 days, respectively, in the open surgery group (p<0.006). Conclusions: Stent-graft repair was associated with lower 30-day mortality and comparable complication rates in older patients with significant comorbidities and a high percentage of emergency operations compared to open surgery. Stent-graft implantation shortens ICU and hospital stays significantly. In the future, subgroups of patients who may experience the greatest benefit from stent-graft repair in the long term should be defined.

Endovascular repair of ruptured abdominal aortic aneurysm: feasibility and impact on early outcome.

PURPOSE Open repair of ruptured abdominal aortic aneurysms (AAAs) still has a high associated mortality rate. The impact of the introduction of endovascular treatment on the early outcomes of ruptured AAAs was examined at a single institution. The suitability of acute endovascular aneurysm repair (EVAR) in patients with ruptured AAAs was also assessed. MATERIALS AND METHODS Retrospective review was conducted in 39 consecutive patients treated for ruptured AAA from 2001 to 2004. The patients were divided into 15 who underwent open repair from 2001 to 2002 (group I) and 24 who were treated with open repair ( n = 13; 54%) or endovascular repair ( n = 11; 46%) from 2003 to 2004 (group II). Hospital charts and computed tomographic scans were reviewed to evaluate the feasibility of EVAR. RESULTS Age, sex, and aneurysm size were similar between the two groups. The 30-day mortality rates were 53% in group I and 8% in group II ( P = .003). Median procedure times were shorter in the patients who underwent EVAR. Intensive care unit stay and hospital stay were 22.0 days ± 29.6 and 29.7 days ± 33.8, respectively, in group I, and 5.6 days ± 4.4 and 16.1 days ± 10.9, respectively, in group II ( P ≤ .03). Eleven patients were found ineligible for EVAR as a result of an unsuitable neck ( n = 5) or iliac arteries ( n = 3) or both ( n = 3). No graft failure was detected during follow-up. CONCLUSIONS After introduction of acute EVAR, a total of 46% of patients with ruptured AAAs were treated with the procedure. Potentially, 54% of patients could have been suitable for EVAR. Endovascular stent-graft implantation has significantly improved outcomes in ruptured AAAs and may therefore be beneficial in the overall treatment strategy in these patients.

Influence of Bicaval Anastomoses on Late Occurrence of Atrial Arrhythmia After Heart Transplantation

BACKGROUND The standard technique for orthotopic heart transplantation includes right and left atrial anastomoses, which potentially disturb the integrity of the donor atria. Consequently, electrophysiologic abnormalities such as atrial flutter and fibrillation may occur even late after heart transplanation. METHODS Over a 3-year period, 39 heart transplantations were performed using a standard right atrial anastomosis (group A), and 40 were done using bicaval anastomoses (group B). In each group, data of 30 consecutive patients with a minimum follow-up of 9 months were reviewed retrospectively to assess the incidence of atrial arrhythmia after hospital discharge. RESULTS Early postoperatively, there was no difference in the duration of temporary pacemaker requirement and incidence of permanent pacemaker implantation (group A, 7%; group B, 7%; not significant) between the two groups. In 12 patients in group A (40%), 16 episodes of atrial flutter and fibrillation were detected 20 to 205 days after heart transplantation. In group B, 1 patient (4%) suffered from atrial fibrillation on day 116 after the operation (p < 0.001). CONCLUSIONS Preservation of the integrity of the right donor atrium by construction of bicaval anastomoses results in a significantly decreased incidence of atrial flutter and fibrillation after heart transplantation when compared with the standard technique.

Ischemic preconditioning prior to myocardial protection with cold blood cardioplegia in coronary surgery

OBJECTIVE Encouraging results on myocardial preconditioning in experimental models of infarction, stunning or prolonged ischemia raise the question whether preconditioning techniques may enhance conventional cardioplegic protection used for routine coronary surgery. METHODS A prospective clinical trial was conducted to investigate the effect of additional ischemic normothermic preconditioning prior to cardioplegic arrest applying cold blood cardioplegia in patients scheduled for routine coronary surgery (3 vessel disease, left ventricular ejection fraction > 50%). Two cross clamp periods of 5 min with the hearts beating in sinus rhythm were applied followed by 10 min of reperfusion, each (n = 7, group I). Inducing moderate hypothermia cold blood cardioplegia was delivered antegradely. In control groups, cold intermittent blood cardioplegia (n = 7, group II) was used alone. Coronary sinus effluents were analyzed for release of creatine kinase (CK), CK-MB, lactate, and troponin T at 1, 3, 6, 9, and 12 h. In addition, postoperative catecholamine requirements were monitored. RESULTS The procedure was tolerated well, and no perioperative myocardial infarction in any of the groups studied occurred. Concentrations of lactate tended to be higher in group I, but this difference was not significant. In addition, no significant differences for concentrations of CK, CK-MB, and troponin T were found. Following ischemic preconditioning an increased dosage of dopamine was required within the first 12 h postoperatively (group I: 2.63 +/- 1.44 microg/kg/min, group II: 0.89 +/- 1.06 microg/kg/min). CONCLUSIONS Combining ischemic preconditioning and cardioplegic protection with cold blood cardioplegia does not appear to ameliorate myocardial protection when compared to cardioplegic protection applying cold blood cardioplegia alone. Inversely, contractile function seemed to be impaired when applying this protocol of ischemic preconditioning.

Coronary artery bypass surgery in diabetic patients.

Abstract  Background: Cardiovascular disease is a major cause of morbidity and mortality in patients with diabetes. This study examines the impact of diabetes on mortality and morbidity following coronary artery bypass surgery. Methods: We retrospectively analyzed 590 consecutive patients after coronary artery bypass grafting in 1998. Reoperations and combined procedures were excluded. A total of 137 diabetic (23.2%) and 453 nondiabetic patients were evaluated. Among the diabetics, 53 were treated with insulin and 84 were non‐insulin‐dependent. Diabetics suffered more frequently from hypertension, peripheral vascular disease, and more often had an increased body mass index (BMI). Results: There was no significant difference in mortality and major complications among insulin‐dependent diabetics, non‐insulin‐dependent diabetics, and nondiabetic patients. Diabetics suffered more often from superficial sternal wound infection and had a higher incidence of superficial wound infections at the vein harvest site. Conclusion: The present study suggests that diabetes increases the risk of superficial wound infections after coronary artery bypass grafting. But diabetics do not necessarily have an increased risk of major complications and mortality. (J Card Surg 2004;19:36‐40)

Therapy for lung failure using nitric oxide inhalation and surfactant replacement

Nitric oxide inhalation and surfactant replacement therapy are relatively new concepts in the treatment of respiratory failure due to hypoxia and reperfusion injury after lung transplantation. We report on a patient in whom reperfusion injury of the lung developed after resuscitation and implantation of a biventricular assist device for sudden cardiac arrest. Lung failure developed within 12 hours after implantation of the biventricular assist device. Lung function was reestablished using combined therapy of nitric oxide and surfactant. Heart transplantation was performed successfully thereafter. This case indicates the potential role of a combined therapy of nitric oxide and surfactant in acute hypoxic lung failure.

Composite valve graft versus separate aortic valve and ascending aortic replacement

To ascertain if the operative technique has any influence on outcome, the surgical results after aortic root replacement using either a composite valve graft (CVG) or a separate graft and valve (SVG) were analyzed. Eighty-four patients received a CVG, and 36 had SVG replacement. The operative mortality rate was 6% for patients receiving a CVG and 3% for SVG replacement (nonsignificant). Follow-up extended to 21 years (mean 124 ± 45 months). The type of the procedure (SVG versus CVG) was not a significant predictor of in-hospital mortality, length of hospital stay, subsequent root dilatation (SVG), anastomotic dehiscence and subsequent surgery. The early and long-term results after CVG or SVG were similar, which reflects proper patient selection.

Mid-Term Results After Endovascular Stent-Grafting of Descending Aortic Aneurysms in High-Risk Patients

PurposeTo analyze our experience with endovascular stent-grafting of descending aortic aneurysms in high-risk patients.MethodsNineteen patients underwent endovascular stent-graft repair of descending aortic aneurysms using the Talent Stent Graft System (Medtronic). All patients were considered high-risk for open surgical repair due to their age, requirement for emergency surgery, and comorbidities. Computed tomography and/or MR tomography were performed at 3, 6 and 12 months postoperatively and thereafter every 12 months.ResultsSecondary technical success was 100%. Thirty-day mortality was 5%. Incidence of postoperative stroke and paraplegia were 5% each. One patient required a second stent-graft due to a type I endoleak during the same hospital stay (primary technical success 95%). All patients have been followed for a median of 20 months. No migration, wire fractures or endoleak appeared during follow-up.ConclusionEndovascular stent-grafting had a low 30-day mortality and morbidity in high-risk patients. One patient developed an aortoesophageal fistula 40 days after stent implantation. Stent-graft repair is a valuable supplement to surgical therapy in high-risk patients.

Early postoperative flow rates after internal thoracic artery grafting for the left coronary artery system

OBJECTIVE The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined. METHODS Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity. RESULTS Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances. CONCLUSIONS The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.