Decrease in serum alkaline phosphatase and prognostic relevance in adult cardiopulmonary bypass

OBJECTIVES

Cardiopulmonary bypass (CPB) induces inflammatory responses, which may lead to the loss of alkaline phosphatase (AP) that is consumed in the process of dephosphorylating detrimental extracellular nucleotides in this proinflammatory state. It has been reported that low postoperative AP levels correlate with increased postoperative support requirement and organ dysfunction after paediatric cardiac surgery. However, little is known about the perioperative development and clinical relevance of AP depletion in adults undergoing CPB.

METHODS

A total of 183 patients with a preoperative left ventricular ejection fraction ≤50% undergoing mitral valve surgery ± concomitant related procedures at the Department of Cardiac Surgery, Medical University of Vienna, between 2013 and 2016 were included in this retrospective analysis. Serum AP measurements at baseline and on postoperative days 1-15 were collected. Absolute and relative drop of AP on postoperative day 1 from baseline was correlated with perioperative and early postoperative parameters. Receiver operating characteristics were used to define suitable predictors and cut-offs for postoperative outcome variables.

RESULTS

Receiver operating characteristics showed a reduction of >50% of baseline AP to predict in-hospital mortality [area under the curve (AUC) 0.807], prolonged intensive care unit stay (>72 h, AUC 0.707), prolonged mechanical ventilation (>24 h, AUC 0.712) and surgery-related dialysis requirement (AUC 0.736). Patients with a perioperative reduction in circulating AP to levels below 50% of baseline had a significantly decreased survival. Patients with high perioperative AP loss had higher preoperative AP levels (P < 0.001), longer CPB duration (P < 0.001) and higher incidence of extracorporeal membrane oxygenation support (P < 0.001).

CONCLUSIONS

Increased perioperative AP loss is associated with adverse early outcome. Prospective trials are needed to determine whether this effect can be counteracted by perioperative AP supplementation.

Intermediate-term outcome of 500 consecutive rapid-deployment surgical aortic valve procedures†

OBJECTIVES

The Edwards INTUITY Valve System is a balloon-expandable bioprosthesis, inspired from the Edwards Magna valve and transcatheter technology, with a subvalvular stent frame to enable rapid deployment. We report a single-centre experience of aortic valve replacement with this novel bioprosthesis.

METHODS

Five hundred consecutive patients, of whom 45.6% were female with a mean age of 73.5 [standard deviation (SD) 7.9 years], with severe aortic stenosis who received a rapid deployment aortic valve between May 2010 and July 2017 were included in a prospective and ongoing database. The median follow-up time was 12 months, and the total accumulated follow-up time was 818 patient years. Preoperative characteristics, operative parameters, survival, valve-related adverse events and valve haemodynamics were assessed.

RESULTS

Thirty-day mortality was 0.8% (4/500), and overall survival at 1, 3 and 5 years was 94%, 89% and 81%, respectively. A minimally invasive surgical approach was chosen in 236 patients (47%), of which 122 (24%) were operated on through an anterior right thoracotomy. Cross-clamp and cardiopulmonary bypass times for isolated aortic valve replacement were 53 (SD 17) and 89 (SD 29) min for full sternotomy as well as 75 (SD 23) and 110 (SD 31) min for minimally invasive surgery approaches (P < 0.001). Mean gradients at discharge, 1, 3 and 5 years were 13 (SD 5), 11 (SD 4), 12 (SD 5) and 11 (SD 3) mmHg, respectively. New pacemaker implantation was necessary in 8.6% of patients. A single case (0.2%) of structural degeneration was registered after 6 years. Valve explantation for non-structural dysfunction or endocarditis occurred in 9 patients (1.8%).

CONCLUSIONS

This rapid deployment aortic valve has shown excellent results concerning haemodynamic performance, durability and safety. Implantation requires specific training, and the rate of pacemaker implantation remains a matter of concern. This novel valve also facilitates minimally invasive approaches and may be beneficial in complex combined procedures.

Outcome of rapid deployment aortic valves: long-term experience after 700 implants

Background

The Edwards Intuity Valve System is a bioprosthesis with a balloon-expandable stent frame which enables rapid-deployment (RD). We aimed to analyze our single-center long-term experience with a follow-up until 9 years after aortic valve replacement (AVR) with this bioprosthesis.

Methods

Between May 2010 and May 2019, 700 consecutive patients with severe aortic stenosis or combined aortic valve disease, implanted with a RD valve at our institution, were included in a prospective database. Median follow-up was 19 months and the total accumulated follow-up was 2,140 patient-years. Pre-operative characteristics, operative parameters, survival rates, valve-related adverse events and valve hemodynamics were assessed.

Results

Mean age was 74±8 years, 45% female. Concomitant procedures were performed in 339 (48.4%) patients. In case of isolated AVR (361/700), a minimally invasive surgical (MIS) approach was conducted in 283 patients (78.4%). Cardio-pulmonary bypass (CPB) and cross-clamp times for isolated AVR were 107.7±28.2 and 73.8±21.3 minutes for MIS approaches and 92.8±28.8 and 57.5±20.6 minutes for full sternotomy (P<0.001), respectively. Mean gradients at discharge, 1, 3 and 5 years were 13±5, 11±4, 12±5 and 13±8 mmHg. New early pacemaker implantation was required in 8.9% of patients. Re-intervention or re-operation with valve explantation for structural degeneration, non-structural dysfunction or endocarditis, occurred in 21 cases (3%). Thirty-day mortality was 0.7% (5/700) and overall survival at 1, 3 and 5 years was 98%, 91% and 76%.

Conclusions

We report excellent long-term results in this updated single center experience for RD aortic valves regarding durability, safety and hemodynamic performance.

Rapid-Deployment Aortic Valves for Patients With a Small Aortic Root: A Single-Center Experience

BACKGROUND

Aortic valve replacement in patients with a small aortic root is a matter of concern in terms of prosthesis-patient mismatch. We evaluated the survival and hemodynamic performance after implantation of a small rapid-deployment aortic valve (EDWARDS INTUITY valve system sizes 19 and 21 mm).

METHODS

Between May 2010 and November 2018, 659 consecutive patients with severe aortic stenosis who received a rapid-deployment valve were included in a prospective and ongoing database. A small aortic bioprosthesis (sizes 19 mm and 21 mm) was implanted in 217 (32.9%) patients (mean age 74.9 ± 7.9 years, 85.3% women). Preoperative characteristics, operative parameters, and postoperative outcomes were assessed.

RESULTS

Mean gradients at discharge and 1 year were 14.8 ± 5.6 mm Hg and 13.6 ± 4.9 mm Hg, respectively. Mean effective orifice area and the indexed effective orifice area at discharge were 1.55 ± 0.36 cm² and 0.87 ± 0.22 cm²/m², respectively, and prosthesis-patient mismatch occurred in 77 (35.5%) patients (25.8% moderate and 9.7% severe). Perioperative mortality was 1.8% (n = 4 of 217) and overall survival at 1 year and 5 years was 91% and 79%, respectively. The presence of any prosthesis-patient mismatch degree did not have a significant influence on overall survival (hazard ratio, 0.95; 95% confidence interval, 0.75-1.19; P = .638). At the last follow-up, mean New York Heart Association functional class was 1.5 ± 0.7 vs 2.8 ± 0.6 at baseline (P < .001).

CONCLUSIONS

Surgical aortic valve replacement with rapid-deployment valves has shown improved results concerning hemodynamic performance, with decreased rates of prosthesis-patient mismatch. We observed excellent early-term and midterm survival and a significant improvement in functional class in this subgroup of patients with a small annulus.

Intravenous Heme Arginate Induces HO-1 (Heme Oxygenase-1) in the Human Heart

Objective- HO-1 (heme oxygenase-1) induction may prevent or reduce ischemia-reperfusion injury. We previously evaluated its in vivo induction after a single systemic administration of heme arginate in peripheral blood mononuclear cells. The current trial was designed to assess the pharmacological tissue induction of HO-1 in the human heart with heme arginate in vivo. Approach and Results- Patients planned for conventional aortic valve replacement received placebo (n=8), 1 mg/kg (n=7) or 3 mg/kg (n=9) heme arginate infused intravenously 24 hours before surgery. A biopsy of the right ventricle was performed directly before aortic cross-clamping and after cross-clamp release. In addition, the right atrial appendage was partially removed for analysis. HO-1 protein and mRNA concentrations were measured in tissue samples and in peripheral blood mononuclear cells before to and up to 72 hours after surgery. No study medication-related adverse events occurred. A strong, dose-dependent effect on myocardial HO-1 mRNA levels was observed (right ventricle: 7.9±5.0 versus 88.6±49.1 versus 203.6±148.7; P=0.002 and right atrium: 10.8±8.8 versus 229.8±173.1 versus 392.7±195.7; P=0.001). This was paralleled by a profound increase of HO-1 protein concentration in atrial tissue (8401±3889 versus 28 585±10 692 versus 29 022±8583; P<0.001). Surgery and heme arginate infusion significantly increased HO-1 mRNA concentration in peripheral blood mononuclear cells ( P<0.001). HO-1 induction led to a significant increase of postoperative carboxyhemoglobin (1.7% versus 1.4%; P=0.041). No effect on plasma HO-1 protein levels could be detected. Conclusions- Myocardial HO-1 mRNA and protein can be dose-dependently induced by heme arginate. Protective effects of this therapeutic strategy should be evaluated in upcoming clinical trials. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT02314780.