Different characteristics of postoperative heart failure after surgery for aortic stenosis and coronary disease

Glutamate infusion associated with reduced rises of p-Copeptin after coronary surgery: Substudy of GLUTAMICS II

BACKGROUND

Glutamate plays a key role for post-ischaemic recovery of myocardial metabolism. According to post hoc analyses of the two GLUTAMICS trials, patients without diabetes benefit from glutamate with less myocardial dysfunction after coronary artery bypass surgery (CABG). Copeptin reflects activation of the Arginine Vasopressin system and is a reliable marker of heart failure but available studies in cardiac surgery are limited. We investigated whether glutamate infusion is associated with reduced postoperative rises of plasma Copeptin (p-Copeptin) after CABG.

METHODS

A prespecified randomised double-blind substudy of GLUTAMICS II. Patients had left ventricular ejection fraction ≤0.30 or EuroSCORE II ≥3.0 and underwent CABG ± valve procedure. Intravenous infusion of 0.125 M L-glutamic acid or saline at 1.65 mL/kg/h was commenced 10-20 min before the release of the aortic cross-clamp and then continued for another 150 min P-Copeptin was measured preoperatively and postoperatively on day one (POD1) and day three. The primary endpoint was an increase in p-Copeptin from the preoperative level to POD1. Postoperative stroke ≤24 h and mortality ≤30 days were safety outcomes.

RESULTS

We included 181 patients of whom 48% had diabetes. The incidence of postoperative mortality ≤30 days (0% vs. 2.1%; p = .50) and stroke ≤24 h (0% vs. 3.2%; p = .25) did not differ between the glutamate group and controls. P-Copeptin increased postoperatively with the highest values recorded on POD1 without significant inter-group differences. Among patients without diabetes, p-Copeptin did not differ preoperatively but postoperative rise from preoperative level to POD1 was significantly reduced in the glutamate group (73 ± 66 vs. 115 ± 102 pmol/L; p = .02). P-Copeptin was significantly lower in the Glutamate group on POD1 (p = .02) and POD 3 (p = .02).

CONCLUSIONS

Glutamate did not reduce rises of p-Copeptin significantly after moderate to high-risk CABG. However, glutamate was associated with reduced rises of p-Copeptin among patients without diabetes. These results agree with previous observations suggesting that glutamate mitigates myocardial dysfunction after CABG in patients without diabetes. Given the exploratory nature of these findings, they need to be confirmed in future studies.

Effect of glutamate infusion on NT-proBNP after coronary artery bypass grafting in high-risk patients (GLUTAMICS II): A randomized controlled trial

BACKGROUND

Animal and human data suggest that glutamate can enhance recovery of myocardial metabolism and function after ischemia. N-terminal pro-brain natriuretic peptide (NT-proBNP) reflects myocardial dysfunction after coronary artery bypass surgery (CABG). We investigated whether glutamate infusion can reduce rises of NT-proBNP in moderate- to high-risk patients after CABG.

METHODS AND FINDINGS

A prospective, randomized, double-blind study enrolled patients from November 15, 2015 to September 30, 2020, with a 30-day follow-up at 4 academic cardiac surgery centers in Sweden. Patients underwent CABG ± valve procedure and had left ventricular ejection fraction ≤0.30 or EuroSCORE II ≥3.0. Intravenous infusion of 0.125 M L-glutamic acid or saline at 1.65 mL/kg/h started 10 to 20 minutes before releasing the aortic cross-clamp, then continued for another 150 minutes. Patients, staff, and investigators were blinded to the treatment. The primary endpoint was the difference between preoperative and day-3 postoperative NT-proBNP levels. Analysis was intention to treat. We studied 303 patients (age 74 ± 7 years; females 26%, diabetes 47%), 148 receiving glutamate group and 155 controls. There was no significant difference in the primary endpoint associated with glutamate administration (5,390 ± 5,396 ng/L versus 6,452 ± 5,215 ng/L; p = 0.086). One patient died ≤30 days in the glutamate group compared to 6 controls (0.7% versus 3.9%; p = 0.12). No adverse events linked to glutamate were observed. A significant interaction between glutamate and diabetes was found (p = 0.03). Among patients without diabetes the primary endpoint (mean 4,503 ± 4,846 ng/L versus 6,824 ± 5,671 ng/L; p = 0.007), and the incidence of acute kidney injury (11% versus 29%; p = 0.005) was reduced in the glutamate group. These associations remained significant after adjusting for differences in baseline data. The main limitations of the study are: (i) it relies on a surrogate marker for heart failure; and (ii) the proportion of patients with diabetes had almost doubled compared to the cohort used for the sample size estimation.

CONCLUSIONS

Infusion of glutamate did not significantly reduce postoperative rises of NT-proBNP. Diverging results in patients with and without diabetes agree with previous observations and suggest that the concept of enhancing postischemic myocardial recovery with glutamate merits further evaluation.

TRIAL REGISTRATION

ClinicalTrials.gov https://clinicaltrials.gov/ct2/show/NCT02592824. European Union Drug Regulating Authorities Clinical Trials Database (Eudra CT number 2011-006241-15).

Utility of NT-proBNP as an objective marker of postoperative heart failure after coronary artery bypass surgery: a prospective observational study

Background

Postoperative heart failure (PHF) is the main cause for mortality after cardiac surgery but unbiased evaluation of PHF is difficult. We investigated the utility of postoperative NT-proBNP as an objective marker of PHF after coronary artery bypass surgery (CABG).

Methods

Prospective study on 382 patients undergoing isolated CABG for acute coronary syndrome. NT-proBNP was measured preoperatively, the first (POD1) and third postoperative morning (POD3). A blinded Endpoints Committee used prespecified criteria for PHF. Use of circulatory support was scrutinized.

Results

After adjusting for confounders PHF was associated with 1.46 times higher NT-proBNP on POD1 (p = 0.002), 1.54 times higher on POD3 (p < 0.0001). In severe PHF, NT-proBNP was 2.18 times higher on POD1 (p = 0.001) and 1.81 times higher on POD3 (p = 0.019). Postoperative change of NT-proBNP was independently associated with PHF (OR 5.12, 95% CI 1.86–14.10, p = 0.002). The use of inotropes and ICU resources increased with incremental quartiles of postoperative NT-proBNP.

Conclusions

Postoperative NT-proBNP can serve as an objective marker of the severity of postoperative myocardial dysfunction. Due to overlap in individuals, NT-proBNP is useful mainly for comparisons at cohort level. As such, it provides a tool for study purposes when an unbiased assessment of prevention or treatment of PHF is desirable.

Trial registration

ClinicalTrials.gov Identifier: NCT00489827https://clinicaltrials.gov/ct2/show/NCT00489827?term=glutamics&draw=2&rank=1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00194-4.

The impact of glutamate infusion on postoperative NT-proBNP in patients undergoing coronary artery bypass surgery: a randomized study

Background

Glutamate, a key intermediate in myocardial metabolism, may enhance myocardial recovery after ischemia and possibly reduce the incidence and severity of postoperative heart failure in coronary artery bypass surgery (CABG). N-terminal pro-B-type natriuretic peptide (NT-proBNP) can be used to assess postoperative heart failure (PHF) after CABG. Our hypothesis was that glutamate enhances myocardial recovery in post-ischemic heart failure and, therefore, will be accompanied by a mitigated postoperative increase of NT-proBNP.

Methods

Substudy of the GLUTAmate for Metabolic Intervention in Coronary Surgery (GLUTAMICS) trial (ClinicalTrials.gov Identifier: NCT00489827) a prospective triple-center double-blind randomized clinical trial on 399 patients undergoing CABG with or without concomitant procedure for acute coronary syndrome at three Swedish Cardiac Surgery centres (Linköping, Örebro, and Karlskrona) from May 30, 2007 to November 12, 2009. Patients were randomly assigned to intravenous infusion of 0.125 M l-glutamic acid or saline (1.65 mL/kg of body weight per hour) intraoperatively and postoperatively. Plasma NT-proBNP was measured preoperatively, the first (POD1) and third postoperative morning (POD3). A Clinical Endpoints Committee, blinded to both intervention and NT-proBNP used prespecified criteria to diagnose PHF. The primary endpoints were the absolute levels of postoperative NT-proBNP and the difference between preoperative and postoperative levels of NT-proBNP.

Results

Overall no significant difference was detected in postoperative NT-proBNP levels between groups. However, in high-risk patients (upper quartile of EuroSCORE II ≥ 4.15; glutamate group n = 56; control group n = 45) glutamate was associated with significantly lower postoperative increase of NT-proBNP (POD3-Pre: 3900 [2995–6260] vs. 6745 [3455–12,687] ng•L⁻¹, p = 0.012) and lower NT-proBNP POD3 (POD3: 4845 [3426–7423] vs. 8430 [5370–14,100] ng•L⁻¹, p = 0.001). After adjusting for significant differences in preoperative demographics, NT-proBNP POD3 in the glutamate group was 0.62 times of that in the control group (p = 0.002). Patients in the glutamate group also had shorter ICU stay (21 [19–26] vs. 25 [22–46] h, p = 0.025) and less signs of myocardial injury (Troponin T POD3 (300 [170–500] vs. 560 [210–910] ng•L⁻¹, p = 0.025).

Conclusions

Post hoc analysis of postoperative NT-proBNP suggests that intravenous infusion of glutamate may prevent or mitigate myocardial dysfunction in high-risk patients undergoing CABG. Further studies are necessary to confirm these findings.

Trial registration Swedish Medical Products Agency 151:2003/70403 (prospectively registered with amendment about this substudy filed March 17, 2007). ClinicalTrials.gov Identifier: NCT00489827 (retrospectively registered) https://clinicaltrials.gov/ct2/show/NCT00489827?term=glutamics&draw=1&rank=1

Minimally invasive management of central ECMO after ascending aortic surgery

A small percentage of ascending aortic surgical procedures require temporary mechanical circulatory support, of which veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is the most established technique. We present a surgical technique for minimally invasive central V-A ECMO management, avoiding resternotomy or ventricular compression, while maintaining antegrade blood flow and permitting sternal closure following ascending aortic surgery.

Post hoc analysis of the glutamics-trial: intravenous glutamate infusion and use of inotropic drugs after cabg

BACKGROUND

Intravenous glutamate reduced the risk of developing severe circulatory failure after isolated coronary artery bypass graft surgery (CABG) for acute coronary syndrome (ACS) in a double-blind randomised clinical trial (GLUTAMICS-ClinicalTrials.gov Identifier: NCT00489827 ). Here our aim was to study if glutamate was associated with reduced the use of inotropes.

METHODS

Post-hoc analysis of 824 patients undergoing isolated CABG for ACS in the GLUTAMICS-trial. ICU-records were retrospectively scrutinised including hourly registration of inotropic drug infusion, dosage and total duration during the operation and postoperatively.

RESULTS

ICU-records were found for 171 out of 177 patients who received inotropes perioperatively. Only one fourth of the patients treated with inotropes fulfilled study criteria for postoperative heart failure at weaning from cardiopulmonary bypass (CPB) or later in the ICU. Inotropes were mainly given preemptively to facilitate weaning from CPB or to treat postoperative circulatory instability (bleeding, hypovolaemia). Except for a significantly lower use of epinephrine there were only trends towards lower need of other inotropes overall in the glutamate group. In patients treated with inotropes (glutamate n = 17; placebo n = 13) who fulfilled study criteria for left ventricular failure at weaning from CPB the average duration of inotropic treatment (34 ± 20 v 80 ± 77 h; p = 0.014) and the number of inotropes used (1.35 ± 0.6 v 1.85 ± 0.7; p = 0.047) were lower in the glutamate group.

CONCLUSIONS

Intravenous glutamate was associated with a minor influence on inotrope use overall in patients undergoing CABG for ACS whereas a considerable and significant reduction was observed in patients with heart failure at weaning from CPB.

Cox-maze IV cryoablation and postoperative heart failure in mitral valve surgery patients. SCAND CARDIOVASC J 2016;51:15-20. [PMID: 27248647 DOI: 10.1080/14017431.2016.1196827]

OBJECTIVE

The indications for and the risk and benefit of concomitant surgical ablation for atrial fibrillation (AF) have not been fully delineated. Our aim was to survey whether the Cox-maze IV procedure is associated with postoperative heart failure (PHF) or other adverse short-term outcomes after mitral valve surgery (MVS).

DESIGN

Consecutive patients with AF undergoing MVS with (n = 50) or without (n = 66) concomitant Cox-maze IV cryoablation were analysed regarding perioperative data and one-year mortality.

RESULTS

The patients in the Maze group were younger, were in lower NYHA classes, had better right ventricular function and had lower pulmonary artery pressure. The Maze group had 30 min longer median cross-clamp time (CCT) and 50% had PHF compared with 33% in the No-maze group, p = 0.09. Two patients in the No-maze group died within one year of surgery. Congestive heart failure (OR 4.3 [CI 95%: 1.8-10], p < 0.0001) and CCT (OR 1.03 [CI 95%: 1.01-1.04], p = 0.001) were associated with PHF.

CONCLUSION

The current data cannot exclude that concomitant cryoablation increases the risk for PHF, possibly by increasing the cross clamp time.

One problem two issues! Left ventricular systolic and diastolic dysfunction in aortic stenosis

Reports suggested that immediate post-aortic valve replacement (AVR); left ventricular (LV) dysfunction may be an important risk for morbidity and mortality in patients requiring positive inotropic support. Several factors have been identified as significant prognostic factors i.e., LV systolic dysfunction, LV diastolic dysfunction (LV-DD), heart failure and myocardial infarction (MI). Specific to pathophysiological changes associated with AS, markers of systolic LV function (e.g., LVEF) have been extensively studied in management, yet only a few studies have analysed the association between LV-DD and immediate post-operative LV dysfunction This review brings together the current body of evidence on this issue.

Impact of hypertension on left ventricular hypertrophy regression and exercise capacity in patients operated for aortic valve stenosis

OBJECTIVES

To assess the influence of concomitant hypertension on left ventricular hypertrophy regression and exercise capacity in patients operated for aortic stenosis.

DESIGN

We performed echocardiography 1 week, 6- and 18-month postoperatively in 78 patients, aged 70 (28-86) years, who received Medtronic Hall (33), Biocor (8), Carpentier-Edwards S.A.V. (14) and Freestyle (23) prosthetic valves for severe aortic stenosis. Forty nine patients participated in treadmill tests with ergospirometry at the 6- and 18-month visits.

RESULTS

Left ventricular mass index was comparably reduced in normotensive and hypertensive patients (34 vs. 40 g/m2 after 6 months, and 43 vs. 46 g/m2 after 18 months, ns). In multiple regression analysis, adjusting for baseline left ventricular mass index, larger reduction in left ventricular mass index was associated with younger age and having a Freestyle prosthesis, but not with gender or history of hypertension (multiple R2=0.68, p < 0.05). Exercise capacity assessed as peak oxygen uptake increased from early to late evaluation in normotensive patients (VO2max 24.27 vs. 27.08 ml/kg/min, p < 0.05) while remained unchanged in hypertensive patients (VO2max 22.2 vs. 21.1 ml/kg/min). In multiple regression analysis, higher improvement in exercise capacity was predicted by male gender, younger age and absence of hypertension, while no independent association was found with Freestyle prosthesis (multiple R2 = 0.37, p < 0.05).

CONCLUSIONS

In patients operated for aortic stenosis, concomitant hypertension is associated with lack of improvement in exercise capacity in spite of early left ventricular hypertrophy reduction comparable to what is found in normotensive patients.

Long-Term Consequences of Postoperative Heart Failure After Surgery for Aortic Stenosis Compared With Coronary Surgery

BACKGROUND

Although postoperative heart failure is a major determinant of operative mortality in cardiac surgery it has received little attention in the literature, and long-term consequences remain to be addressed. Therefore, the impact of postoperative heart failure on long-term survival in relation to other risk factors was studied.

METHODS

All patients undergoing aortic valve replacement (AVR) for aortic stenosis from 1995 through 2000 in the southeast region of Sweden (n = 398) were compared with a cohort, matched for age and sex, undergoing coronary artery bypass grafting (CABG [n = 398]). Risk factors for 5-year mortality were analyzed.

RESULTS

Forty-five AVR and 47 CABG patients required treatment for postoperative heart failure. Thirty-day, 1-year, and 5-year mortality in patients with and without postoperative heart failure after AVR were 6.7% versus 1.4% (p = 0.05), 8.9% versus 4.0% (p = 0.13), and 42.2% versus 14.2% (p < 0.0001) respectively. Corresponding results in the CABG group were 21.3% versus 1.1% (p < 0.0001), 25.5% versus 3.1% (p < 0.0001), and 36.2% versus 11.1% (p = 0.0015). Postoperative heart failure, preoperative renal dysfunction, procedure-associated stroke, body mass index less than 19 kg/m2, older age, preoperative atrial fibrillation, and preoperative anemia turned out as independent risk factors for 5-year mortality after AVR. In the CABG group, postoperative heart failure, diabetes mellitus, older age, and procedure-associated stroke emerged as independent risk factor for 5-year mortality.

CONCLUSIONS

Postoperative heart failure was associated with high early mortality after CABG whereas the grave consequences of postoperative heart failure after AVR for aortic stenosis became evident only with time.

Risk Factors for Postoperative Heart Failure in Patients Operated on for Aortic Stenosis

BACKGROUND

Risk factors for postoperative heart failure (PHF) have not been specifically studied in valve surgery although it has been acknowledged that patient variables may have a more profound influence on postoperative outcome than valve-related factors.

METHODS

All patients undergoing isolated aortic valve replacement for aortic stenosis from January 1995 to December 2000 in the southeast region of Sweden were studied (n = 398). Forty-five patients with aortic valve replacement required treatment for PHF. Univariate and multivariate logistic regression analysis was carried out to identify risk factors for PHF.

RESULTS

Thirty-day mortality was 6.7% versus 1.4% for patients with and without PHF, respectively (p = 0.05). With regard to clinical presentation of aortic stenosis, angina was associated with reduced risk, whereas history of congestive heart failure increased the risk for PHF. Five preoperative (hypertension, history of congestive heart failure, severe systolic left ventricular dysfunction, pulmonary hypertension, preoperative hemodynamic instability) and two intraoperative (aortic cross-clamp time, intraoperative myocardial infarction) variables were identified as independent risk factors for PHF. Patient-prosthesis mismatch did not influence the risk of PHF significantly.

CONCLUSIONS

Postoperative heart failure was associated with a marked increase in postoperative mortality and morbidity. Risk factors for PHF were variables indicating preexisting myocardial dysfunction, increased right or left ventricular afterload, and intraoperative myocardial injury. Our results highlight issues concerning cross-clamp time and myocardial protection, particularly for patients with preoperatively compromised myocardial function. Asymptomatic patients with significant aortic stenosis should be considered for surgery before substantial echocardiographic evidence of left ventricular dysfunction or increased pulmonary artery pressure develops.