Sven Peterss

Hypothermic circulatory arrest with selective antegrade cerebral perfusion in ascending aortic and aortic arch surgery: A risk factor analysis for adverse outcome in 501 patients

OBJECTIVEnThis study was undertaken to identify preoperative and intraoperative risk factors influencing outcome after operations requiring hypothermic circulatory arrest with selective antegrade cerebral perfusion in a single center.nnnMETHODSnBetween November 1999 and March 2006, a total of 501 consecutive patients (median age 64 years, range 20-86 years, 320 male) underwent aortic arch surgery with moderate hypothermic circulatory arrest (25 degrees C +/- 2 degrees C) and additional selective antegrade cerebral perfusion (14 degrees C) at our institution for various indications (256 aneurysms, 153 acute and 23 chronic type A aortic dissections, 66 other). Of these, 181 were emergency operations. Statistical analysis was carried out to determine risk factors for 30-day mortality as well as for temporary and permanent neurologic dysfunction.nnnRESULTSnOverall mortality was 11.6%. Permanent neurologic dysfunction occurred in 48 patients (9.6%); temporary neurologic dysfunction was detected in 67 patients (13.4%). Multivariate analysis revealed age (P = .001, odds ratio 1.08), reoperation (P = .006, odds ratio 3.58), femoral arterial cannulation (P = .004, odds ratio 2.87), and cardiopulmonary bypass duration (P < .001, odds ratio 1.009) as risk factors for mortality. Permanent neurologic dysfunction was associated with preoperative renal insufficiency (P = .029, odds ratio 2.79) and operation time (P < .001, odds ratio 1.005), whereas temporary neurologic dysfunction occurred in patients with coronary artery disease (P = .04, odds ratio 2.29), emergency surgery (P = .001, odds ratio 4.09), and increasing hypothermic circulatory arrest duration (P = .01, odds ratio 1.015).nnnCONCLUSIONnModerate hypothermic circulatory arrest in combination with cold selective antegrade cerebral perfusion is an adequate tool for neuroprotection during aortic surgery. Nevertheless, the safety of this technique is limited for patients with long intraoperative durations, advanced age, and multiple comorbidities. This technique, which avoids profound core temperatures, has become an alternative to simple deep hypothermic circulatory arrest.

Ascending aortic cannulation in acute aortic dissection type A: the Hannover experience

OBJECTIVEnThe incidence of embolic events and of cerebral malperfusion in aortic dissection type A (AADA) must be viewed in the context of the existence of a number of possible cannulation techniques. Since femoral cannulation is thought to be associated with a higher risk of perfusion of the false lumen and retrograde embolization, techniques establishing antegrade flow may provide a better option. We describe herein our experience with ascending aortic cannulation in this special patient population.nnnMETHODSnBetween November 1999 and February 2006, 122 patients underwent operation for AADA with arterial access via the dissected ascending aorta. The aorta was cannulated at the site of the minimal distances of the dissected layers. Double purse-string sutures were used to support the cannula. Pressure monitoring in both radial arteries as well as bilateral cerebral oxygen saturation measurement helped to identify malperfusion after establishment of cardiopulmonary bypass. Aortic arch as well as aortic root surgery was performed, as dictated by the pathology. Selective antegrade cerebral perfusion and moderate hypothermia were used for brain and body protection.nnnRESULTSnMalperfusion occurred in three patients (2.5%). Hospital mortality was 15% for the entire cohort (18 patients). Permanent neurological dysfunction was detected in 15 patients (12%), whereas temporary neurological dysfunction occurred in 21 (17%). Total arch replacement was performed in 31 patients (25%).nnnCONCLUSIONnDirect cannulation of the ascending aorta is an easy and safe method in patients with AADA. This technique, which also avoids retrograde flow in the downstream aorta, is an alternative to time-consuming axillary artery access.

Isolated surgical aortic valve replacement after previous coronary artery bypass grafting with patent grafts: is this old-fashioned technique obsolete?

AIMnHigh-risk patients are currently being evaluated for various catheter-based aortic valve replacement (AVR) techniques. To identify an individual patients risk, scores such as the EuroSCORE or STS risk calculator (RC) are used. The aim of the present study was to evaluate the surgical results in patients who underwent isolated AVR via a median re-sternotomy after prior CABG.nnnPATIENTS AND METHODSnBetween 01/96 and 01/08, 349 patients underwent AVR as a redo procedure. One hundred and thirty patients had undergone previous CABG; in 39 patients (29 male, median age 75 (60-84)) preoperative coronary angiography revealed open grafts with no need for additional revascularization (30 had LIMA grafts). These patients underwent isolated AVR. Operative mortality was calculated using the standard and logistic EuroSCORE, and the STS RC.nnnRESULTSnOperative (30-day mortality) was 5% (2 patients). Mean calculated predicted mortality rates for the cohort were: 12+/-3% for the standard, and 32+/-21% for the logistic EuroSCORE, and 10+/-4% according to the STS RC. Receiver operated characteristics (ROC) analysis revealed 100% specificity for standard EuroSCOREs up to 12.5%, logistic EuroSCOREs up to 39.7% and up to 17.45% for STS RC, with a sensitivity of 69.5%, 75% and 97.2%, respectively. The STS RC showed significant better prediction of mortality than the EuroSCOREs (p=0.006).nnnCONCLUSIONSnConventional AVR as a redo procedure after CABG with patent grafts can be performed with excellent results and lower mortality than estimated. Results of newer catheter-based AVR approaches should not to be compared with artificial scores to justify high morbidity rates.

The impact of deep and moderate body temperatures on end-organ function during hypothermic circulatory arrest.

OBJECTIVEnHypothermic circulatory arrest (HCA) at different temperatures is a protection technique for operations involving the aortic arch. In combination with selective cerebral perfusion, higher arrest temperatures for the remaining body may be permitted. However, the ischaemic/reperfusion injury (I/R) in various organ systems, other than the brain, related to the specific HCA temperature has so far not been evaluated.nnnMETHODSnFourteen pigs were randomly assigned to 60 min of sole HCA at 20 or 30 °C temperature, weaned from cardiopulmonary bypass (CPB) and followed 4h after HCA. Besides complex haemodynamic monitoring, laser-Doppler spectrophotometry for measuring capillary blood flow, tissue oxygen saturation and post-capillary venous filling pressures of the bowel was installed. At the end of experiment, organs were perfusion fixated and harvested.nnnRESULTSnDuring the entire experiment, haemodynamics revealed no differences between the groups. CPB bypass times were 177 ± 12 min in the 20 °C and 158 ± 11 min in the 30 °C group, respectively (p = 0.02). During reperfusion, lactate levels were initially significantly higher in the 30 °C animals (p = 0.001) but subsequently declined. Microcirculatory blood flow and velocity in the bowel were significantly reduced during cooling and reperfusion (p < 0.05), but were independent of final HCA temperature. Histological evaluation revealed significantly more oedema formation in the bowel wall of the 30 °C animals (p = 0.05).nnnCONCLUSIONSnHigher levels of circulating lactate levels during reperfusion indicate less effective organ protection at 30 than at 20 °C after 60 min of HCA. This is further substantiated by histological evidence for a more pronounced oedema inflammatory response within the bowel wall.

Acute Treatment of ST-Segment-Elevation Myocardial Infarction: Is There a Role for the Cardiac Surgeon?

BACKGROUNDnSeveral attempts from single institutions to treat acute myocardial infarctions with bypass surgery never reached widespread acceptance in the cardiology and surgical community. Owing to a variety of new surgical techniques, this old dogma has to be reconsidered under the light of patient-adjusted optimal treatment algorithms.nnnMETHODSnBetween August 2002 and August 2007, 112 patients, mean age of 66 years (range, 41 to 85 years), underwent emergency coronary artery bypass grafting (untreatable or rejected by the referring cardiologists within 48 hours after onset of symptoms). Thirty-seven patients (33%) exhibited cardiogenic shock, and 18 (16%) had prior cardiopulmonary resuscitation. Preoperative support by intraaortic balloon pump was initiated in only 10%, and 65% had left main stem stenosis.nnnRESULTSnAll patients showed a significant elevation of cardiac markers (creatine kinase-MB) and ST-segment elevation. The mean number of grafts was 2.4 (range, 1 to 4). The cardiopulmonary bypass time ranged from 48 to 261 minutes. Intraaortic balloon pump for weaning from extracorporeal circulation was used in 42 patients (38%); 3 patients needed extracorporeal membrane oxygenation support. Postoperative complications included rethoracotomy for bleeding in 4% and stroke in 2%. Thirty-day mortality was 20% in the whole group, 30% in the group with cardiogenic shock, and 15% in those without hemodynamic deterioration (p = 0.044). The multivariate analysis revealed the preoperative need for catecholamines as the only risk factor for 30-day mortality (odds ratio, 6.4; 95% confidence interval, 2 to 21; p = 0.002).nnnCONCLUSIONSnEmergency coronary artery bypass grafting in patients with acute myocardial infarction can be performed with acceptable results, especially in those without cardiogenic shock. Therefore, operative revascularization should not be considered only as a rescue therapy.

Immediate surgical coronary revascularisation in patients presenting with acute myocardial infarction

BackgroundThe number of patients presenting with acute myocardial infarction (AMI) and being untreatable by interventional cardiologists increased during the last years. Previous experience in emergency coronary artery bypass grafting (CABG) in these patients spurred us towards a more liberal acceptance for surgery. Following a prospective protocol, patients were operated on and further analysed.MethodsWithin a two year interval, 127 patients (38 female, age 68±12 years, EuroScore (ES) II 6.7±7.2%) presenting with AMI (86 non-ST-elevated myocardial infarction (NSTEMI), 41 STEMI) were immediately accepted for emergency CABG and operated on within six hours after cardiac catheterisation (77% three-vessel-disease, 47% left main stem stenosis, 11% cardiogenic shock, 21% preoperative intraaortic balloon pump (IABP), left ventricular ejection fraction 48±15%).Results30-day-mortality was 6% (8 patients, 2 NSTEMI (2%) 6 STEMI (15%), p=0.014). Complete revascularisation could be achieved in 80% of the patients using 2±1 grafts and 3±1 distal anastomoses. In total, 66% were supported by IABP, extracorporal life support (ECLS) systems were implanted in two patients. Logistic regression analysis revealed the ES II as an independent risk factor for mortality (p<0.001, HR 1.216, 95%-CI-Intervall 1.082-1.366).ConclusionsQuo ad vitam, results of emergency CABG for patients presenting with NSTEMI can be compared with those of elective revascularisation. Complete revascularisation obviously offers a clear benefit for the patients. Mortality in patients presenting with STEMI and cardiogenic shock is substantially high. For these patients, other concepts regarding timing of surgical revascularisation and bridging until surgery need to be taken into consideration.

Conventional aortic valve replacement in patients with concomitant coronary artery disease and previous coronary artery bypass grafting in the era of interventional approaches

OBJECTIVEnIn patients with symptomatic aortic valve stenosis and a high estimated operative risk due to previous coronary artery bypass grafting (CABG) procedures, interventional aortic valve implantation techniques may ultimately prove superior. However, recent studies have revealed increased mortality and impaired survival in patients with concomitant coronary artery disease (CAD).nnnMETHODSnBetween January 1996 and May 2010, 60 patients (73 ± 6 years, 15 female (25%)) underwent conventional operation 9 ± 6 years after CABG for symptomatic aortic valve stenosis (European System for Cardiac Operative Risk Evaluation, EuroSCORE) standard 11 ± 3%, logistic 27 ± 17%, Society of Thoracic Surgeons (STS) Score 19 ± 8%). Coronary angiography revealed open grafts and no need for further revascularization in all patients. High-risk patients were identified (log. EuroSCORE≥ 20%, n = 34) and divided by age (< 75 years, n=15; ≥ 75 years, n=19) for sub-group analysis. Follow-up for all 60 patients was performed according to the current guidelines: quality of life was assessed using the Minnesota Living with Heart Failure Questionnaire (MLHFQ).nnnRESULTSnThirty-day-mortality was 5% (n=3). During follow-up (100% complete), 18 patients died. Thus, 1-, 3- and 5-year survival was 91%, 77%, and 69%, respectively. No differences in survival could be detected between the two high-risk groups. Quality of life revealed excellent results for the entire cohort, as well as both high-risk groups.nnnCONCLUSIONSnConventional surgery in patients with symptomatic aortic valve stenosis after previous CABG can be performed with excellent results despite a high calculated risk, independent of age. Although conventional surgery is technically more demanding and associated with substantial surgical trauma, it is justified by the excellent survival and high quality of life in this high-risk patient cohort.

Cryopreserved human allografts (homografts) for the management of graft infections in the ascending aortic position extending to the arch

OBJECTIVESnThe management of infected Dacron grafts in the ascending aortic position involving the aortic arch and aortic root remains a technical challenge. Total replacement of the infected graft material with cryopreserved homografts appears to be an effective treatment strategy for these patients.nnnMETHODSnSeventeen consecutive patients were operated on for infection of their ascending aortic graft where the aortic arch was also involved 26 ± 33 months after initial surgery, in 70%, for type A aortic dissection (12 acute aortic dissection type A and 1 chronic aortic dissection type A). The aortic root was additionally affected in 14 patients. Computed tomography and echocardiography follow-up was performed in all patients.nnnRESULTSnHospital mortality was 24% (n = 4). Cardiopulmonary bypass and aortic cross-clamp times were 288 ± 128 and 165 ± 78 min, respectively. In 14 patients, the aortic root was replaced. Hypothermic circulatory arrest was necessary in all patients (41 ± 25 min) with additional cold selective antegrade cerebral perfusion in 14 (41 ± 30 min). During follow-up, 1 patient died due to a cerebral haemorrhage at 3 months and another at 4 years, of pulmonary embolism. Two patients were successfully reoperated on for degeneration of the aortic valve at 16 and 94 months; 1 patient had an early degeneration of the homograft and needed re-replacement with a homograft. In 2 other patients, a stent graft had to be placed to cover the distal anastomosis between the homograft and native aorta. In all others, recent follow-up revealed no degeneration of the implanted homografts.nnnCONCLUSIONSnSurgery for infected Dacron grafts in the ascending aortic position with involvement of the arch can be performed with an acceptable perioperative mortality. In case of degeneration of the valve, reoperations can be performed with good results in experienced hands. Therefore, we consider the concept of complete explantation of all infected material and replacement with homografts a successful treatment strategy. Nevertheless, close follow-up of the patients is mandatory so as not to miss any degeneration or reinfection of the implanted grafts.

Lymphoscintigraphic localization of a high-output chylus leak after bilateral lung transplantation

We report the case of a 59-year-old man who developed a high-output chylothorax after bilateral lung transplantation. For exact localization of the leak, lymphoscintigraphy was performed before re-thoracotomy by application of Tc-99m-nanocolloid single-photon emission computed tomography (SPECT/CT), which showed a radioactive accumulation in the medial lower thoracic cavity, localized below the right upper pulmonary vein. This technique is actually an overly complex, time-consuming procedure for proper surgical planning in selected cases.

Aortic root surgery in septuagenarians: impact of different surgical techniques

BackgroundTo evaluate the impact and safety of different surgical techniques for aortic root replacement (ARR) on early and late morbidity and mortality in septuagenarians undergoing ARR.MethodsNinety-five patients (73.8 ± 3.2 years) were operated and divided into three groups according to the aortic root procedure; MECH-group (n = 51) patients with a mechanical composite graft, BIO-group (n = 22) patients with a customized biological composite graft, and REIMPL-group (n = 22) patients with a valve sparing aortic root reimplantation (David I). In 42.1% (40/95) of these patients the aortic arch was replaced. Follow-up was completed in 95.2% (79/83) of in-hospital survivors.ResultsHospital mortality was 12.6% (12/95) in the entire population (MECH. 15.7% (8/51), BIO 19.7% (4/22), REIMPL 0% (0/22); p = 0.004). Two patients died intraoperatively. The most frequent postoperative complications were prolonged mechanical ventilation ((>48 h) in 16.8% (16/93) (MECH. 7% (7/51), BIO 36.4% (8/22), REIMPL 4.5% (1/22); p = 0.013) and rethoracotomy for postoperative bleeding in 12.6% (12/95) (MECH. 12% (6/51), BIO 22.7% (5/22), REIMPL 4.5% (1/22); p = 0.19). Nineteen late deaths (22.9%) (19/83) (MECH 34.8% (15/43), BIO 16.7% (3/18), REIMPL 4.5% (1/22); p = 0.012) occurred during a mean follow-up of 41 ± 42 months (MECH 48 ± 48 months, BIO 25 ± 37 months, REIMPL 40 ± 28 months, p = 0.028). Postoperative NYHA class decreased significantly (p = 0.017) and performance status (p = 0.027) increased for the entire group compared to preoperative values.ConclusionOur data indicate that valve sparing aortic root reimplantation is safe and effective in septuagenarians, and is associated with low early and late morbidity and mortality.