Clinical outcome of urgent coronary artery bypass grafting

Surgical coronary revascularization in patients with COVID‐19; complications and outcomes: A retrospective cohort study

Background and Aims

Coronary artery disease is high‐risk comorbidity of COVID‐19 infection. Nonelective coronary artery revascularization in COVID‐19 patients carries substantial risk. Therefore, it is essential to understand the risk factors and outcomes fully. This study aims to evaluate the prognosis of coronary artery bypass grafting (CABG) surgery in patients with COVID‐19.

Methods

This retrospective cohort study assesses 171 patients who underwent urgent and emergent CABG in Tehran Heart Center from March 2020 to September 2021. The patients were allocated to cases and controls based on COVID‐19 infection status. Demographic and clinical features, alongside the complications and outcomes, were compared between the two groups.

Results

According to diagnostic criteria, 62 patients were diagnosed with COVID‐19 (Case) and 109 patients had no COVID diagnosis (Control). Regarding the demographics and risk factors, hypertension was more prevalent among patients with COVID‐19 (64.5% compared to 43.1% p= 0.007). Length of hospital stay, ventilation time, and intensive care unit (ICU) stay time were significantly higher in patients infected with COVID‐19. Postoperative complications, including stroke, atrial fibrillation, pleural effusion, blood transfusion, and Inotrope use, were significantly higher in the case group. Mortality rates were also higher in COVID‐19 patients with an odds ratio of 1.53; however, this difference is not statistically significant (p: 0.44, 95% CI = 0.50–4.01).

Conclusion

COVID‐19 is associated with a significantly higher hospital stay, ventilation time, and ICU stay. Mortality rates are also higher, albeit insignificantly. Various postoperative complications are also higher with COVID‐19.

Pulmonary complications following cardiac surgery

Coronary heart disease is a common diseases of atherosclerosis. Despite the development of noninvasive therapies and the advancement of pharmacological methods and extensive drug regimens, coronary artery bypass grafting surgery is still the ultimate treatment option in many patients. Among the various complications following open heart surgery, one of the common difficulties is pulmonary complications associated with subsequent morbidity and mortality, which should be studied according to preoperative, perioperative, and postoperative factors. Preoperative factors include genetics, age, family history of pulmonary disease, smoking, coexisting disease, etc. Perioperative factors include surgical procedures like sternotomy incision, cardioplegia, and internal mammary artery harvesting; anaesthesia procedure effects like pulmonary collapse, maintenance drugs and morphine administration; and cardiopulmonary bypass pump by systemic inflammatory response syndromes. And finally, postoperative factors, especially mediastinitis and the role of nursing in the intensive care unit. Pulmonary complications after cardiac surgery include atelectasis, pleural effusions, pneumonia, pulmonary oedema, cardiogenic pulmonary oedema, acute respiratory distress syndrome, pulmonary embolism, phrenic nerve injury, pneumothorax, sternal wound infection, and mediastinitis, with different outbreaks in patients reported. Although the preoperative, perioperative, and postoperative factors play an important role in the occurrence of these complications, the preoperative factors, as factors that can be adjusted, should be considered more than the others and explained to the patient, and the preoperative patient’s assessment should be noted. Also, postoperative care with the goal of reducing infections and pulmonary complications should be addressed by the nursing team.

Intravenous ivabradine versus placebo in patients with low cardiac output syndrome treated by dobutamine after elective coronary artery bypass surgery: a phase 2 exploratory randomized controlled trial

BACKGROUND

Low cardiac output syndrome (LCOS) is a severe condition which can occur after cardiac surgery, especially among patients with pre-existing left ventricular dysfunction. Dobutamine, its first-line treatment, is associated with sinus tachycardia. This study aims to assess the ability of intravenous ivabradine to decrease sinus tachycardia associated with dobutamine infused for LCOS after coronary artery bypass graft (CABG) surgery.

METHODS

In a phase 2, multi-center, single-blind, randomized controlled trial, patients with left ventricular ejection fraction below 40% presenting sinus tachycardia of at least 100 beats per minute (bpm) following dobutamine infusion for LCOS after CABG surgery received either intravenous ivabradine or placebo (three ivabradine for one placebo). Treatment lasted until dobutamine weaning or up to 48 h. The primary endpoint was the proportion of patients achieving a heart rate (HR) in the 80- to 90-bpm range. Secondary endpoints were invasive and non-invasive hemodynamic parameters and arrhythmia events.

RESULTS

Nineteen patients were included. More patients reached the primary endpoint in the ivabradine than in the placebo group (13 (93%) versus 2 (40%); P = 0.04). Median times to reach target HR were 1.0 h in the ivabradine group and 5.7 h in the placebo group. Ivabradine decreased HR (112 to 86 bpm, P <0.001) while increasing cardiac index (P = 0.02), stroke volume (P <0.001), and systolic blood pressure (P = 0.03). In the placebo group, these parameters remained unchanged from baseline. In the ivabradine group, five patients (36%) developed atrial fibrillation (AF) and one (7%) was discontinued for sustained AF; two (14%) were discontinued for bradycardia.

CONCLUSION

Intravenous ivabradine achieved effective and rapid correction of sinus tachycardia in patients who received dobutamine for LCOS after CABG surgery. Simultaneously, stroke volume and systolic blood pressure increased, suggesting a beneficial effect of this treatment on tissue perfusion.

TRIAL REGISTRATION

European Clinical Trials Database: EudraCT 2009-018175-14 . Registered February 2, 2010.

Four-chamber pacing in patients with poor ejection fraction but normal QRS durations undergoing open heart surgery

BACKGROUND

Poor ejection fraction (EF) comprises a critical risk factor in cardiac bypass surgery (CABG). It has been unclear, whether biventricular or four-chamber pacing confers benefit upon patients with intact atrioventricular and interventricular conduction especially following surgery.

METHODS

Twenty-one consecutive patients with an EF <or= 35% underwent hemodynamic evaluation (continuous pressures and thermodilution) 3, 6, and 18 hours post-CABG and biatrial (AA), biatrial-right ventricular (AAV), and biatrial-biventricular (AAVV) pacing were compared.

RESULTS

Patients (65 +/- 9 years) presented with an average EF of 29.5% (15-35%). 514 measurements of cardiac index (CI) were taken. Nineteen patients (91%) showed highly significant increases in CI with AAVV as compared to AA pacing (P < 0,001) at all times post surgery. The increase in CI with pacing mode varied from 6% to 25% and decreased with time following surgery. No consistent difference in CI was seen between four-chamber (AAVV) and biventricular pacing (AVV). The QRS-widths prior to surgery never exceeded 120 ms; postoperatively QRS-complexes widened in all patients on average by 15.9 ms +/-6 and returned to starting values by 48 hours.

CONCLUSIONS

Biventricular pacing improves CI in patients with poor EF following cardiac surgery in the absence of preoperative atrioventricular- or interventricular conduction block. This benefit decreases with time after surgery as the QRS width returns to preoperative values. Four-chamber pacing did not confer additional benefit as compared to biventricular pacing in this series. Biventricular pacing should be considered as an adjunct in patients with critically low EF undergoing cardiac surgery.