Postrevascularization recovery of fatty acid utilization in ischemic myocardium: a randomized clinical trial of potassium channel opener

Revascularisation for Ischaemic Cardiomyopathy

Coronary artery disease is a leading cause of heart failure with reduced ejection fraction. Coronary artery bypass grafting appears to provide clinical benefits such as improvements in quality of life, reductions in readmissions and MI, and favourable effects on long-term mortality; however, there is a significant short-term procedural risk when left ventricular function is severely impaired, which poses a conundrum for many patients. Could percutaneous coronary intervention provide the same benefits without the hazard of surgery? There have been no randomised studies to support this practice until recently. The REVIVED-BCIS2 trial (NCT01920048) assessed the outcomes of percutaneous coronary intervention in addition to optimal medical therapy in patients with ischaemic left ventricular dysfunction and stable coronary artery disease. This review examines the trial results in detail, suggests a pathway for investigation and revascularisation in ischaemic cardiomyopathy, and explores some of the remaining unanswered questions.

Serial change in perfusion-metabolism mismatch after coronary artery bypass grafting

OBJECTIVE

Myocardial ischemia is known to suppress fatty acid metabolism and favor glucose metabolism. However, changes in myocardial metabolism after coronary revascularization are not fully elucidated.

METHODS

Thirty-eight patients with coronary artery disease were retrospectively enrolled. These patients had undergone stress perfusion single photon emission computed tomography (SPECT) and ¹²³I-BMIPP SPECT in both the short-term (6.4 ± 4.7 months) and mid-term (29.9 ± 7.2 months) after isolated coronary artery bypass grafting. Tracer uptake was graded using a 17-segment, 5-point scoring model. Serial changes in SRS (summed rest score), SDS (summed difference score), the BMIPP score (total defect score of BMIPP), and the mismatch score (BMIPP score-SRS) were evaluated. In addition, persistent perfusion-metabolism mismatch (PM) was defined as mismatch score minus SDS of 3 or more during the mid-term postoperative period. The clinical parameters associated with PM were examined.

RESULTS

From short- to mid-term postoperative period, the extent of infarcted myocardium (SRS) did not change significantly (7.8 ± 8.0 to 7.1 ± 7.0, P = 0.117). The extent of ischemic myocardium (SDS), the BMIPP score and the mismatch score, which reflects perfusion-metabolism mismatch, were significantly improved (2.0 ± 2.8 to 0.7 ± 1.0, P = 0.010; 12.2 ± 9.0 to 9.5 ± 7.9, P < 0.001; 4.4 ± 3.7 to 2.5 ± 2.6, P < 0.001; respectively). Remarkably, perfusion-metabolism mismatch persisted in 13 patients (34%) even in the mid-term postoperative period. eGFR and SYNTAX score were independent predictors of persistent perfusion-metabolic mismatch in multivariable analysis (OR = 0.951, 95% CI 0.898-0.985, P = 0.010 and OR = 1.126, 95% CI 1.011-1.254, P = 0.031, respectively). The mismatch score both in the short- and mid-term significantly correlated with SYNTAX score (r = 0.400 and r = 0.472, respectively).

CONCLUSIONS

Fatty acid metabolism disturbance improved from short- to mid-term postoperative period in patients with successful reperfusion by coronary artery bypass grafting. However, in patients with severe atherosclerosis, impaired fatty acid metabolism was sustained until the mid-term postoperative period, even though ischemia had resolved.

Effects of mitochondrial ATP-sensitive potassium channel activation (nicorandil) in patients with angina pectoris undergoing elective percutaneous coronary interventions: A meta-analysis of randomized controlled trials

AIMS

Nicorandil, which is a mitochondrial ATP-sensitive potassium channel opener, is believed to improve perioperative myocardial injury (PMI) in patients undergoing percutaneous coronary intervention (PCI), but recent studies have shown that nicorandil treatment did not improve functional and clinical outcomes in patients with angina pectoris who underwent elective PCI. We performed a meta-analysis to investigate the protective effect of nicorandil on perioperative injury in patients with angina pectoris who underwent elective PCI.

METHODS

The Medline, EMBASE, and Cochrane databases were searched for randomized clinical trials examining the effects of nicorandil. Two investigators independently selected suitable trials, extracted data, and assessed trial quality.

RESULTS

Seven studies of patients undergoing elective PCI, comprising a total of 979 patients, were included in this review. The results showed that nicorandil did not reduce the levels of markers of myocardial injury (standardized mean difference [SMD] 0.31 [95%CI -0.6, 1.22] for creatine kinase-MB [CK-MB] and 1.29 [95%CI -2.18, 4.76] for troponin I [TNI]), perioperative complications (relative risk [RR] 0.91 [95%CI 0.46-1.81]), target vessel revascularization (RR 0.79 [95%CI 0.50-1.25]) or major adverse cardiac events (MACE) (RR 0.83 [95%CI 0.49-1.43]). Nicorandil did reduce the corrected TIMI frame count (SMD-0.30 [95%CI -0.52, -0.09]).

CONCLUSION

Although nicorandil did not reduce the overall incidence of perioperative complications and the incidence of major adverse cardiac events (MACE) in patients with angina pectoris who underwent elective PCI, it could still improve no reflow and slow coronary flow.

Improvement of myocardial fatty acid metabolism by oral nicorandil in hemodialysis patients without coronary artery disease

BACKGROUND

We investigated the potential of oral nicorandil to improve myocardial fatty acid metabolism assessed by single-photon emission computed tomography (SPECT) using (123)I-β-methyliodophenyl pentadecanoic acid (BMIPP) in hemodialysis patients without obstructive coronary artery disease (CAD).

METHODS

This study was based on a cohort study of 155 hemodialysis patients with angiographic absence of obstructive CAD, with analysis performed in 100 propensity-matched patients (54 men and 46 women, 64 ± 10 years); 50 with oral administration of nicorandil (15 mg/d, nicorandil group) and 50 without (control). BMIPP SPECT was performed every year after angiography. Uptake on SPECT was graded in 17 segments on a five-point scale (0 normal, 4 absent) and assessed as BMIPP summed scores (SS).

RESULTS

Over a mean follow-up period of 5.3 ± 1.9 years, we observed 25 cardiac deaths among 100 propensity-matched patients. Myocardial uptake of BMIPP in SPECT improved in the nicorandil group compared with the control group from 2 years of administration. In Kaplan-Meier survival analyses, free survival rate from cardiac death was higher in patients with a BMIPP SS improvement rate of ≥20% compared to those with ≥0% <20% or with <0% BMIPP SS improvement rate. At multiple logistic analysis, a ≥20% BMIPP SS improvement rate was positively associated with serum albumin concentration and oral nicorandil.

CONCLUSIONS

Long-term oral nicorandil may inhibit cardiac death by improving myocardial fatty acid metabolism in hemodialysis patients without obstructive CAD.

Clinical potential of oral nicorandil to improve myocardial fatty acid metabolism after percutaneous coronary intervention in hemodialysis patients

BACKGROUND/AIMS

The assessment of myocardial fatty acid metabolism impairment by single-photon emission computed tomography (SPECT) using (123)I-β-methyliodophenyl-pentadecanoic acid (BMIPP) might predict the risk of cardiac death in hemodialysis patients. We investigated the potential of oral nicorandil to improve myocardial fatty acid metabolism after percutaneous coronary intervention (PCI) in this population.

METHODS

We evaluated 128 hemodialysis patients who had obtained coronary revascularization by PCI (90 men and 38 women, 66 ± 9 years). Participants for the analysis were randomly assigned to either the nicorandil (n = 63) or control group (n = 65). BMIPP SPECT was performed every year after coronary revascularization by PCI. Uptake on SPECT was graded in 17 segments on a 5-point scale (0, normal; 4, absent) and assessed as BMIPP summed scores (SS).

RESULTS

The incidence of cardiac death was lower (p = 0.004) in the nicorandil group (7/63, 11.1%) than in the control group (21/65, 32.3%) during a mean follow-up of 2.7 ± 1.4 years. BMIPP SS reduction rates improved in the nicorandil group compared with the control group from 3 years of administration. In Kaplan-Meier analyses, free survival rate of cardiac death was higher in patients with a ≥20% BMIPP SS reduction rate as compared with those with a <20% BMIPP SS reduction rate (p = 0.0001). In multiple logistic analysis, oral administration of nicorandil was associated with ≥20% reduction rates of BMIPP SS (odds ratio 2.823, p = 0.011).

CONCLUSION

Long-term oral administration of nicorandil may improve impaired myocardial fatty acid metabolism after coronary revascularization by PCI in hemodialysis patients.

Pharmacological prevention of peri-, and post-procedural myocardial injury in percutaneous coronary intervention

In recent years, percutaneous coronary intervention (PCI) has become a well-established technique for the treatment of coronary artery disease. PCI improves symptoms in patients with coronary artery disease and it has been increasing safety of procedures. However, peri- and post-procedural myocardial injury, including angiographical slow coronary flow, microvascular embolization, and elevated levels of cardiac enzyme, such as creatine kinase and troponin-T and -I, has also been reported even in elective cases. Furthermore, myocardial reperfusion injury at the beginning of myocardial reperfusion, which causes tissue damage and cardiac dysfunction, may occur in cases of acute coronary syndrome. Because patients with myocardial injury is related to larger myocardial infarction and have a worse long-term prognosis than those without myocardial injury, it is important to prevent myocardial injury during and/or after PCI in patients with coronary artery disease. To date, many studies have demonstrated that adjunctive pharmacological treatment suppresses myocardial injury and increases coronary blood flow during PCI procedures. In this review, we highlight the usefulness of pharmacological treatment in combination with PCI in attenuating myocardial injury in patients with coronary artery disease.