Peter L. Haldenwang

Impact of preoperative statin therapy on adverse postoperative outcomes in patients undergoing cardiac surgery: a meta-analysis of over 30 000 patients

AIMSnTo determine the strength of evidence for preoperative statin use for prevention of adverse postoperative outcomes in patients undergoing cardiac surgery.nnnMETHODS AND RESULTSnAfter literature search in major databases, 19 studies were identified [three RCT (randomized prospective clinical trials), 16 observational] that reported outcomes of 31 725 cardiac surgery patients with (n = 17 201; 54%) or without (n = 14 524; 46%) preoperative statin therapy. Outcomes that were analysed included early all-cause mortality (30-day mortality), myocardial infarction (MI), atrial fibrillation (AF), stroke and renal failure. Odds ratio (OR) with 95% confidence intervals (95%CI) were reported using fixed or random effect models and publication bias was assessed. Preoperative statin therapy resulted in a 1.5% absolute risk reduction (2.2 vs. 3.7%; P < 0.0001) and 43% odds reduction for early all-cause mortality (OR 0.57; 95%CI: 0.49-0.67). A significant reduction (P < 0.01) in statin pretreated patients was also observed for AF (24.9 vs. 29.3%; OR 0.67, 95%CI: 0.51-0.88), stroke (2.1 vs. 2.9%, OR 0.74, 95%CI: 0.60-0.91), but not for MI (OR 1.11; 95%CI: 0.93-1.33) or renal failure (OR 0.78, 95%CI: 0.46-1.31). Funnel plot and Eggers regression analysis (P = 0.60) excluded relevant publication bias.nnnCONCLUSIONnOur meta-analysis provides evidence that preoperative statin therapy exerts substantial clinical benefit on early postoperative adverse outcomes in cardiac surgery patients, but underscores the need for RCT trials.

Minimally invasive transapical aortic valve implantation and the risk of acute kidney injury.

BACKGROUNDnThe new technique of minimally invasive transapical aortic valve implantation (TAP-AVI) deals with high-risk patients and despite the absence of cardiopulmonary bypass it might lead to renal impairment. The aim of this study was to estimate the risk of the development of acute kidney injury (AKI) after TAP-AVI and to identify possible risk factors with regard to the morbidity and mortality of the patients.nnnMETHODSnData of 30 consecutive patients undergoing TAP-AVI were recorded and followed up for 8 weeks. Postoperative AKI has been defined according to RIFLE criteria. Two patients on chronic hemodialysis have been followed up.nnnRESULTSnOf 28 patients, AKI occurred in 16 patients (57%). Statistical analysis revealed no influence on the risk of developing AKI caused by the dose of applicated contrast medium (p = 0.09), the patients age (p = 0.5), or the existence of diabetes (p = 0. 16). Analysis concerning the relationship between a preexisting coronary heart disease and AKI showed a tendency to be associated with a higher risk of the development of AKI (70% preexisting congenital heart disease in the AKI group versus 50%; p = 0.28). Only a preoperative serum creatinine greater than 1.1 mg/dL was a strong predictor for developing AKI (p < 0.01). Length of stay in the intensive care unit and the complete length of hospital stay revealed no difference with regard to postoperative development of AKI though statistical analysis showed a trend to a higher mortality in the AKI group (27% vs 6%); univariate analysis did not reach statistical significance (p = 0.13).nnnCONCLUSIONSnThe TAP-AVI seems to be a feasible procedure for high-risk patients with a clear risk of developing AKI. Patients at risk should be identified and, if indicated, already preoperatively treated in collaboration with the attending nephrologists.

Impact of hypothermic selective cerebral perfusion compared with hypothermic cardiopulmonary bypass on cerebral hemodynamics and metabolism

OBJECTIVEnHypothermic selective cerebral perfusion (SCP) is widely used for cerebral protection during aortic arch surgery, but the effect of the absence of systemic perfusion on cerebrovascular dynamics it has never been established. This study explored the physiology of prolonged SCP compared to hypothermic cardiopulmonary bypass (HCPB) in pigs.nnnMETHODSnIn this blinded protocol, 29 juvenile pigs (20-23 kg) were randomized after cooling on cardiopulmonary bypass (CPB) to 20 degrees C. Group I pigs (n=14) underwent 90 min of SCP, while group II (HCPB, n=15) underwent total body perfusion. Fluorescent microspheres were injected during perfusion and recovery, enabling calculation of total and regional cerebral blood flow (CBF). Cerebrovascular resistance (CVR), oxygen consumption and intracranial pressure (ICP) were also monitored.nnnRESULTSnCBF decreased significantly (P=0.0001) during cooling, but remained at significantly higher levels with SCP than with HCPB throughout perfusion and recovery (P<0.0001). CVR was significantly lower with SCP than with HCPB throughout perfusion (P=0.04). Oxygen consumption fell significantly with cooling (P=0.0001), remained low during perfusion, and rebounded promptly with rewarming; with SCP it was significantly higher than with HCPB throughout the perfusion interval (P=0.03), and remained higher thereafter. ICP rose significantly less with SCP than with HCPB (P=0.02).nnnCONCLUSIONnWe conclude that, compared with HCPB, SCP results in beneficial cerebral vasodilatation, as evidenced by significantly higher CBF and oxygen consumption during SCP, by prompt recovery of oxygen consumption after rewarming, and by significantly lower ICP during perfusion and in the post-bypass period.

Recent improvements in outcome with the Novacor left ventricular assist device.

BACKGROUNDnThe Novacor implantable, electrically powered, wearable, left ventricular assist device (LVAD) has been used as a bridge to transplantation at our institution since 1994. Recent changes in protocol have resulted in a decreased incidence of infections, thromboembolism, and mortality.nnnMETHODSnWe reviewed the medical records of all 43 patients who received implantable LVADs at the Mount Sinai Medical Center. After 1998, a number of protocol modifications were instituted. Vascular grafts were changed from a low-porosity, woven polyester (Cooley) to a gelatin-sealed, knitted polyester graft (Vascutek), the devices were implanted pre-peritoneally rather than in the posterior rectus sheath, and extensive drainage of the chest and pre-peritoneal pocket was used. The following anti-coagulation regimen was used: low-molecular-weight Dextran for 1 day, initiated after chest tube drainage <50 cc/hour; then IV heparin for 10 to 14 days, beginning at 500 U/hour, slowly increasing partial thromboplastin time to 1.5 to 2 x control; and finally Coumadin, maintaining the international normalized ratio at 2.5 to 3.5. Daily aspirin, 325 mg, was begun on post-operative Day 7. We compared 22 patients who electively underwent surgery before the changes, Group I, with 18 patients treated thereafter, Group II.nnnRESULTSnGroups I and II were well matched with regard to age (47 vs 44 years); cause of heart failure (idiopathic, 50% vs 44%; ischemic, 50% vs 56%), and duration of support (79 vs 76 days). The incidence of thromboembolic cerebrovascular events was significantly less in Group II (6%) than in Group I (23%), p = 0.025. The incidence of bleeding increased mildly in Group I. Pocket infections occurred in 27% of Group I patients vs 11% of Group II patients, p = 0.018. Only 2 patients (11%) in Group II died while receiving device support, vs 7 (32%) in Group I, p = 0.019.nnnCONCLUSIONSnOur results indicate that pre-peritoneal implantation, use of a new generation of vascular grafts, extensive drainage, and a more restricted anti-coagulation regimen improve outcome after Novacor LVAD implantation for advanced heart failure.

Successful Transapical Aortic Valve Replacement in a Patient With a Previous Mechanical Mitral Valve Replacement

In this case we illustrate our experience with transapical minimal invasive aortic valve replacement in a patient who previously underwent mitral valve replacement. The implantation did not interfere with the existing prosthesis and could even be used as a further landmark, helping height positioning of the aortic valve.

Transapical minimally invasive aortic valve implantation and conventional aortic valve replacement in octogenarians.

OBJECTIVEnTranscatheter aortic valve implantation (TAVI) has been developed to minimize the operative trauma in high-risk patients. Patient selection for TAVI is still subject to debate and octogenarians are often regarded as high-risk patients.nnnMETHODSnIn this single-center study, data of 169 octogenarians who received conventional AVR (90) or TAVI (79) have been analyzed retrospectively according to the endpoint definitions of the Valve Academic Research Consortium to answer the following questions: (a) Should patients due to their age of 80 years or older be considered as high risk? (b) Is the EuroSCORE a suitable tool for estimating mortality after AVR or TAVI in octogenarians? (c) Is TAVI the procedure of choice for octogenarians?nnnRESULTSnTAVI patients showed higher comorbid conditions concerning an existing renal dysfunction (31 vs. 56%, p = 0.001), peripheral vascular disease (6 vs. 30%, p < 0.001), diabetes (19% vs. 49%, p < 0.001), a decreased ejection fraction (LVEF < 30%: 2 vs. 13%, p < 0.05), and pulmonary hypertension (23 vs. 48%; p < 0.005) with an increase of the perioperative risk represented by logistic EuroSCORE (AVR 11% ± 1.27 vs. TAVI 38% ± 1.35; p < 0.0005) and STS Score (7% ± 0.52 vs. 14% ± 0.56; p < 0.0005). All-cause and cardiovascular-cause in-hospital or 30-day mortality was 5.6% (n = 5) and 3.4% (n = 3) in the AVR cohort and 8.8% (n = 7) and 7.6% (n = 6) in TAVI-patients (p = 0.55; p = 0.31), respectively. The overall combined safety endpoint at 30 days was 22.2% (n = 20) in AVR patients and 29.1% (n = 23) with regard to the TAVI group (p = 38). Analysis of cerebrovascular complications, vascular complications, and pacemaker revealed no significant differences. In the AVR group, actuarial survival at 6 months and 1 and 2 years was 89, 78, and 74%, respectively. Data of the TAVI patients are only available for a follow-up of 6 months and revealed a survival of 85%.nnnCONCLUSIONnAVR and TAVI in octogenarians show comparable results, but the analyzed cohorts differ significantly in their risk profile. The results indicate an overrated perioperative mortality using the EuroSCORE but on the other hand logistic EuroSCORE represents articulately the different risk profile of the two groups. For this reason, we consider the EuroSCORE still to be a useful tool for preoperative risk assessment. Moreover, octogenarians cannot per se be considered as true high risk patients. Differentiated clinical judgment is most important for reasonable decision making.

Temperature Dependence of Cerebral Blood Flow for Isolated Regions of the Brain During Selective Cerebral Perfusion in Pigs

BACKGROUNDnHypothermic circulatory arrest (HCA) and antegrade selective cerebral perfusion (ASCP) are utilized for cerebral protection during aortic surgery. However, no consensus exists regarding optimal ASCP-temperature showing a tendency toward higher values during the last years. This study investigates regional changes of cerebral blood flow (CBF) during ASCP at two temperatures.nnnMETHODSnIn this blinded study, 20 pigs (35 to 37 kg) were randomized to two groups. Animals were cooled to 10 minutes of HCA followed by 60 minutes of ASCP. Afterward the animals were perfused at 25 degrees C and 30 degrees C according to the study group. Fluorescent microspheres were injected at seven time points during the experiment to calculate total and regional CBF. Hemodynamics, cerebrovascular resistance (CVR) and cerebral metabolic rate of oxygen (CMRO(2)) were assessed. Tissue samples from the cortex, cerebellum, hippocampus, and pons were taken for microsphere count.nnnRESULTSnThe CBF and CMRO(2) decreased significantly (p < 0.002) during cooling in both groups; it was significantly higher throughout ASCP in the 30 degrees C versus the 25 degrees C group (p = 0.0001). These findings were similar among all brain regions, certainly at different levels. The CBF increased significantly (p = 0.002) during the early period of ASCP for analyzed regions and decreased significantly (p = 0.034) below baseline after 60 minutes of ASCP, reaching critical levels in the hippocampus and neocortex. The hippocampus turned out to have the lowest CBF, while the pons showed the highest CBF. Thirty minutes and more ASCP provides less CBF compared with baseline values at both temperatures.nnnCONCLUSIONSnAntegrade selective cerebral perfusion improves CBF in all regions of the brain for a limited time. Our study characterizes the brain specific hierarchy of blood flow during ASCP. These dynamics are highly relevant for clinical strategies of perfusion.

Annular rupture leading to fatal complications in an elderly patient with calcified aortic and mitral annulus undergoing transapical aortic valve implantation.

This case illustrates the awareness that must be taken of the high morphological risk due to the calcifications of both, the aortic and mitral annulus in elderly patients when performing transapical aortic valve implantation. In an 86-year-old, multimorbid woman (logistic EuroSCORE = 27%) with symptomatic aortic stenosis (annular diameter = 23.4 mm) and severe mitral annular calcification, the implantation of a 26-mm Edwards SAPIEN (Edwards Lifesciences, Irvine, California, United States) valve in aortic position was primary successful, with no paravalvular leakage, valve instability, or coronary malperfusion. Second, a persisting transmural bleeding led to hypovolemic shock, which could not be stabilized even after going on cardiopulmonary bypass, and the patient died in the operation room. The autopsy showed a subvalvular ventricular rupture due to a transmural perforation of the calcified fibrotic annulus during valvuloplasty.

Pulmonary trunk perforation during transapical minimal invasive aortic valve replacement

In this case report we illustrate our experience with a perforation of the pulmonary trunk during a transapical aortic valve implantation in a single case. The patient suffered from an aortic valve stenosis and was accepted for a minimally invasive procedure because of multiple comorbidities. After unproblematic transapical placement of the aortic valve, a venous bleeding from the anterolateral wound was observed. Median sternotomy showed a bleeding out of the pulmonary trunk that could be stopped with purse-string sutures. The further course of the patient was uneventful.