[Baroreflex activation therapy. A novel interventional approach to treat heart failure with reduced ejection fraction]

Sympathovagal imbalance plays an important role in the progression of heart failure with reduced ejection fraction. Baroreflex activation therapy (BAT), i. e. electrical stimulation of baroreceptors located at the carotid sinus, can reduce sympathetic and enhance parasympathetic tone. Large animal studies on BAT demonstrated improvements in cardiac function, arrhythmogenic risk and a survival benefit compared to untreated controls. The recently published Neo Randomized Heart Failure Study, the first multicenter, randomized and controlled trial of optimal medical and device therapy alone or plus BAT in patients with a left ventricular ejection fraction ≤ 35 %, demonstrated a reasonable safety profile of BAT in this severely ill patient population and no relevant interactions with other devices. The study found significant improvements in the New York Heart Association (NYHA) class of heart failure, quality of life as well as 6 min walking distance and data pointed to a reduction in hospitalization rates. Moreover, N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were significantly reduced. This review gives an overview on BAT for the treatment of heart failure with reduced ejection fraction, from the rationale and animal experiments to the most recent clinical data and future perspectives.

The acute effect of IABP-induced pulsatility on coronary vascular resistance and graft flow in critical ill patients during ECMO

AIM

The combination of the two cardiac support mechanisms of intra-aortic balloon pumping (IABP) and non-pulsatile circulatory extracorporeal membrane oxygenation (ECMO) has been confirmed to improve efficacy of the cardiac support as a whole. However, reports on benefits of diastolic augmentation on coronary vascular bed and graft flowmetry during concomitant use of IABP and ECMO are lacking. The aim of this study was to evaluate the acute impact of IABP support on coronary vascular resistance (CVR) and coronary bypass flows (CBF) in high-risk patients with peripheral ECMO following coronary artery bypass grafting (CABG).

METHODS

In eight emergency CABG patients (mean age=67.8±1.9 years; gender: six male and two female; EF=25.5±2.4%) requiring mechanical circulatory support with ECMO hemodynamic parameters, CVR, CBF, diastolic filling index (DFI), graft flow reserve (GFR), and pulsatility index (PI) were analyzed with and without diastolic augmentation using a transit time flowmeter.

RESULTS

The addition of IABP to ECMO decreased CVR significantly by 6.5%±1.9% compared to baseline with ECMO alone (1.62±0.2 versus 1.78±0.2; P<0.0045). Accordingly, significant higher mean CBF were found during IABP assist, resulting in a 21.6%±2.6% increase (60.7±8.7 mL/min with versus 51.3±7.4 mL/min without IABP; P<0.0001). IABP also significantly increased DFI by 9.8±0.9% (73.2%±1.4% with versus 66.7%±1.3% without IABP; P<0.0001). GFR was recruited during IABP in all grafts (GFR>1). There were no statistically significant differences in PI with and without IABP assistance (2.6±0.1 versus 2.5±0.2).

CONCLUSION

IABP-induced pulsatility significantly improves diastolic filling index and mean coronary bypass graft flows by lowering coronary vascular resistance during non-pulsatile peripheral ECMO. The combination of ECMO with IABP may provide more optimal myocardial oxygen conditions resulting in an improved efficacy of the cardiac support as a whole in critical ill patients with postcardiotomy myocardial dysfunction following CABG.

Myocardial protection in cardiac surgery patients requiring prolonged aortic cross-clamp times: a single-center evaluation of clinical outcomes comparing two blood cardioplegic strategies

AIM

The aim of this study was to evaluate the impact of intermittent warm (IWC) versus intermittent cold blood cardioplegia (ICC) in high-risk patients that require prolonged periods of aortic cross-clamping during on-pump cardiac surgery.

METHODS

From 3527 consecutive patients undergoing on-pump cardiac surgery, 520 patients were retrospectively identified that required prolonged aortic cross-clamp ≥ 75 min. Myocardial protection was performed with ICC (N.=280) or IWC (N.=240). Groups were compared regarding clinical outcomes, myocardial injury (CK-MB, cTnT) and multivariate analysis was performed to assess the impact of applied cardioplegia on 30-day all-cause mortality, cardiac death, perioperative myocardial injury (PM) and major adverse cardiac events (MACE).

RESULTS

Demographic data, mean logistic Euroscore, aortic-cross-clamping and CPB time were comparable between groups. Patients with ICC needed more intraoperative defibrillations, had more postoperative blood transfusions and a prolonged hospital stay when compared to the IWC-group (P < 0.05). Thirty-day all-cause mortality tended to be higher in IWC (11% vs. 6%; P = 0.083) with significantly higher cardiac mortality (9% vs. 4%; P=0.015) compared to ICC. Myocardial injury was more pronounced in the IWC-group with a higher incidence of PMI (IWC: 17% vs. ICC:6%; P < 0.05) and MACE (IWC:37% vs. ICC:25%; P < 0.05). Groups did not differ regarding other postoperative clinical outcomes. Multivariate analysis revealed IWC to be independently predictive (P < 0.05) for 30-day all-cause mortality (OR:2.42; 95% CI:1.04-5.05), cardiac death (OR:3.57; 95% CI:1.49-8.85), MACE (OR:1.87; 95% CI:1.22-2.87) and PMI (OR:3.46; 95% CI:1.86-6.41).

CONCLUSION

ICC results in less myocardial damage and reduced postoperative cardiac mortality and morbidity in patients requiring extended periods of aortic-cross-clamping during on-pump cardiac surgery, suggesting superior cardioprotection when compared to IWC.

[Extracorporeal life support given to a 16-year-old girl with cystic fibrosis, candida pneumonia and acute respiratory distress syndrome]

HISTORY

Small bowel resection had to be performed because of an acute ileus in a 16-year old girl with mucoviscidosis. Severe respiratory insufficiency developed and she was transferred to the intensive care unit.

INVESTIGATIONS

The clinical signs of a severe ARDS were demonstrated: Horowitz index < 200, pO (2) 57 mm Hg, FiO (2) 1,0, pCO (2) 82 mm Hg. Candida serology was positive (titer 1 : 5120), and there was a leukocytosis (20 000/µl), hypalbuminemia (14 g/l) and elevation of C-reactive protein (190 mg/l).

TREATMENT AND COURSE

Because all non invasive treatment options had failed to improve the patient's condition, an extracorporal membrane oxygenation (ECMO) device was connected. Seven days later, after the pulmonary situation had improved, the device was successfully removed; the patient was discharged in a satisfactory condition after another month.

CONCLUSION

ECMO is a another treatment option for serious ARDS in infection-related worsening of pulmonary cystic fibrosis.

[Cave canulam et dilatationem. Cardiopulmonary resuscitation and surgical repair of a vessel perforation following central venous catheterization]

A 58-year-old female patient was scheduled for minimally invasive cardiac surgery. For drainage of venous blood to the heart-lung machine insertion of a central venous large diameter catheter was a prerequisite. During insertion into the right internal jugular vein by the anesthesiologist a life-threatening perforation of the subclavian artery occurred. The patient suffered hemorrhagic shock and advanced cardiac life support was carried out for approximately 18 min. Immediate surgical repair was successful and the originally planned operation was then performed. Concurrently, mild therapeutic hypothermia was established for 24 h to protect the cerebrum. Within 4 days the patient recovered without any neurological deficits.