Current perspectives on mechanical circulatory support.

Mechanical circulatory support gained a significant value in the armamentarium of heart failure therapy because of the increased awareness of the prevalence of heart failure and the tremendous advances in the field of mechanical circulatory support during the last decades. Current device technologies already complement a heart transplant as the gold standard of treatment for patients with end-stage heart failure refractory to conservative medical therapy. This article reviews important aspects of mechanical circulatory support therapy and focuses on currently debated issues.

Off-Pump Coronary Artery Bypass Grafting and Stroke-Exploratory Analysis of the GOPCABE Trial and Methodological Considerations.

BACKGROUND: Coronary artery bypass grafting (CABG) without cardiopulmonary bypass (off-pump CABG) may reduce severe adverse events including stroke. METHODS: In the German Off-Pump Coronary Artery Bypass Grafting in Elderly patients trial, the rate of major adverse cardiovascular events was compared in 2,394 elderly (≥ 75 years) patients undergoing CABG with (on-pump) or without (off-pump) cardiopulmonary bypass. This exploratory post-hoc analysis investigated the impact of surgical aortic manipulation on the rate of stroke. RESULTS: There was no significant difference in the rate of stroke within 30 days after surgery between both groups (off-pump: 2.2%; on-pump: 2.7%; odds ratio [OR]: 0.83 [0.5-1.38]; p = 0.47). Within the off-pump group, different degrees of aortic manipulation did not lead to significant different stroke rates (tangential clamping: 2.3%; OR 0.86 [0.46-1.60]; clampless device: 1.8%; OR 0.67 [0.26-1.75]; no aortic manipulation: 2.4%; OR 0.88 [0.37-2.14]). An aggregate analysis including more than 10,000 patients out of the four recent major trials also yielded comparable stroke rates for on- and off-pump CABG (off-pump: 1.4%; on-pump: 1.7%; OR 0.87 [0.64-1.20]). CONCLUSION: Within recent prospective randomized multicenter trials off-pump CABG did not result in lower stroke rates. The possible intrinsic benefit of off-pump CABG may be offset by the complexity of the operative therapy as well as the multiple pathomechanisms involved in perioperative stroke.

Female sex is not a risk factor for post procedural mortality in coronary bypass surgery in the elderly: A secondary analysis of the GOPCABE trial.

OBJECTIVE: Female sex is considered a significant risk in cardiac surgery and is included in the majority of scores for risk assessment. However, the evidence is controversial and older women undergoing cardiac surgery have not specifically been investigated. We assessed the influence of female sex on surgical risk (30-day mortality) in a secondary analysis of the GOPCABE trial (German Off-Pump Coronary Artery Bypass grafting in the Elderly (GOPCABE) trial, comparing on- to off-pump) and also evaluated its impact on risk prediction from commonly used risk scores. METHODS: We performed logistic regression analyses on the GOPCABE trial population, where patients were randomized to either on- or off-pump CABG. The study was performed in 12 cardiac surgery centers in Germany and analyzed 2394 patients having undergone CABG at age ≥75 years (1187 on-pump, 1207 off-pump). Of the 2394 patients, 755 (32%) were women. The logistic EuroSCORE and the German KCH score were calculated as expected (E) mortality and values were compared to observed (O) 30-day mortality (O/E ratio). RESULTS: There was no difference in mortality or major cardiovascular adverse events after 30 days between men and women for both on- and off-pump CABG (men: on- vs. off-pump OR = 0.90, 95%-CI: [0.63;1.27]; women: on- vs. off-pump OR = 1.07, 95%-CI: [0.62;1.87]). Therefore, groups were combined for further analyses. Both men and women had considerable and similar comorbidities. Expected mortality was significantly higher for women than for men (logistic EuroSCORE: 8.88±6.71% vs. 7.99±6.69%, p = 0.003; KCH score: 4.42±3.97% vs. 3.57±3.65%, p = 0.001). However, observed mortality rates (O) tended to be even lower in women (2.1% vs. 3.0%). The O/E ratio was closer to 1 in men than in women (0.84 vs. 0.47). Excluding female sex from the risk models increased O/E ratio to 0.69. CONCLUSIONS: Female sex is not a risk factor in coronary bypass surgery in the GOPCABE population. The result is the same for on- and off-pump surgery. Since female sex is a component of most risk scores, the findings may identify a potential inaccuracy in current surgical risk assessment, specifically for elderly women. TRIAL REGISTRATION: Clinicaltrials.gov GOPCABE trial No. NCT00719667.

Sleep-disordered breathing in patients undergoing transfemoral aortic valve implantation for severe aortic stenosis.

BACKGROUND: We examined the prevalence of sleep-disordered breathing (SDB) in patients with severe aortic valve stenosis (AS) and the impact of transfemoral aortic valve implantation (TAVI) on SDB. METHODS: 79 patients underwent cardiorespiratory polygraphy (PG) before TAVI (CoreValve™), 62 of them a second PG after the procedure. RESULTS: Forty-nine (62 %) patients had obstructive sleep apnea (OSA), 25 (32 %) central sleep apnea (CSA), and 5 (6 %) presented without significant SDB (apnea-hypopnea index (AHI) < 5/h). Among the 62 patients evaluated before and after TAVI, 36 (58 %) had OSA, 22 (36 %) CSA, and 4 patients (7 %) no SDB. AHI was significantly higher in CSA patients than in OSA patients (34.5 ± 18.3 vs. 18.0 ± 12.6/h, p < 0.001). Successful TAVI had a significant impact on CSA but not on OSA: CSA patients with optimal TAVI results experienced a significant reduction in central respiratory events (AHI 39.6 ± 19.6-23.1 ± 16.0/h, p = 0.035), while no changes were detected in OSA patients (AHI 18.8 ± 13.0-20.25 ± 13.4/h, p = 0.376). In contrast, in patients who developed at least moderate periprosthetic aortic regurgitation (AR > I), CSA increased significantly (AHI 26.3 ± 13.2-39.2 ± 18.4/h, p = 0.036), whereas no acute change was seen in patients with OSA (AHI 10.5 ± 7.8-12.5 ± 5.0/h, p = 0.5). CONCLUSION: OSA and CSA are prevalent in more than 90 % of patients undergoing TAVI for severe aortic valve stenosis. Successful TAVI had no significant impact on OSA but improved CSA. In case of an acute change from pressure overload (aortic stenosis) to acute volume overload (aortic regurgitation after TAVI), central, but not obstructive, sleep apnea deteriorated.

A modified technique for implantation of the HeartWare™ left ventricular assist device when using bivalirudin anticoagulation in patients with acute heparin-induced thrombocytopenia.

In patients with acute heparin-induced thrombocytopenia (HIT) needing urgent cardiac surgery, bivalirudin is recommended as a first-line strategy for intraoperative anticoagulation. However, due to the unique elimination process of bivalirudin, careful adjustment of the perfusion and surgical strategy is mandatory as blood stasis in the circuit or prolonged interruption of areas or compartments containing blood from the systemic circulation may result in thrombus formation. We report here a modified surgical strategy for the implantation of the HeartWare™ left ventricular assist device, which avoids prolonged disconnection of the blood-filled device from the systemic blood flow, so that bivalirudin can be safely used as anticoagulant.

DuraHeart magnetically levitated centrifugal left ventricular assist system for advanced heart failure patients.

The implantable left ventricular assist system (LVAS) using pulsatile pump technology has become an established therapeutic option for advanced heart failure patients. However, there have been technological limitations in some older designs, including a high incidence of infection and mechanical failures associated with moving parts, and the large size of both implantable pump and percutaneous cable. A smaller rotary blood pump emerged as a possible alternative to a large pulsatile pump to overcome some of these limitations. The technological advancement that defines the third-generation LVAS was the elimination of all mechanical contacts between the impeller and the drive mechanism. The DuraHeart LVAS is the world's first third-generation implantable LVAS to obtain market approval (CE-mark), which combines a centrifugal pump and active magnetic levitation. The initial clinical experience with the DuraHeart LVAS in Europe demonstrated that it provided significantly improved survival (85% at 6 months and 79% at 1 year), reduced adverse event rates and long-term device reliability (freedom from device replacement at 2 years: 96 +/- 3%) over pulsatile LVAS.

Risk factors for mediastinitis after cardiac surgery - a retrospective analysis of 1700 patients.

BACKGROUND: Mediastinitis is a rare, but serious complication of cardiac surgery. It has a significant socioeconomic impact and high morbidity. The purpose of this study was to determine pre-, intra-, and postoperative predictors of mediastinitis. METHODS AND RESULTS: In 1700 consecutive patients, who underwent cardiac surgery in 2001, 49 variables were retrospectively assessed. Forty-five patients (2.65%, 95% CI [1.88; 3.41]) developed postoperative mediastinitis. None of these patients died during their hospitalization. Multivariate analysis identified three of the 49 variables as highly significant independent predictors for the development of mediastinitis: obesity (OR 1.03, 95% CI [1.01; 1.04] p = 0.001), chronic obstructive pulmonary disease (OR 3.30, 95% CI [1.58; 6.88], p = 0.001), and bilateral grafting of the internal mammary artery (OR 3.18, 95% CI [1.20; 8.43] p = 0.02). The model is reliable in terms of its goodness of fit, it also discriminates well. Additionally, univariate analysis identified diabetes mellitus, CCS class and the number of intraoperatively transfused units of fresh frozen plasma as variables with a significant impact. CONCLUSION: The present study suggests that bilateral IMA grafting, chronic obstructive pulmonary disease and obesity are important predictors of mediastinitis.