Validity of inducible ischaemia as a surrogate for adverse outcomes in stable coronary artery disease

The impact of stress testing to guide PCI in patients with chronic coronary disease

BACKGROUND

Guidelines and international appropriate use criteria increasingly endorse non-invasive stress testing to evaluate patients with suspected chronic coronary disease (CCD). We sought to review the real-world utilisation of non-invasive stress testing and investigate whether their use prior to PCI associates with outcomes in patients with CCD.

METHODS

Consecutive patients from a multicentre registry who underwent PCI for CCD between 2006 and 2018 were included. Clinical characteristics and outcomes were stratified according to whether stress testing was performed prior to PCI (stress vs no-stress groups). The primary outcome was 3-year all-cause mortality.

RESULTS

Among the 8251 patients included, 4970 (60.2 %) underwent pre-PCI stress testing and this proportion increased over time (p-for-trend<0.001). The stress group had a lower prevalence of prior revascularization, myocardial infarction, or heart failure, and a lower incidence of triple vessel disease, in stent re-stenosis, and ACC/AHA class B2/C lesions (all p < 0.001). When comparing post-procedural outcomes, the stress group had lower rates of arrhythmia (1.5 % vs 2.6 %, p = 0.001), new heart failure (0.2 % vs 0.8 %, p = 0.001), renal impairment, and a shorter length of stay (1.6 vs 2.1 days, p < 0.001). Mortality at 3-years was lower in those undergoing PCI following stress testing (5.8 % vs 8.8 %, p < 0.001). After adjusting for key clinical variables, stress guided revascularization was associated with a significantly lower risk of 3-year mortality (adjusted Hazard Ratio 0.77, 95 % CI 0.64-0.92).

CONCLUSIONS

In patients with CCD, PCI guided by non-invasive stress testing is increasingly utilized and associated with improved survival. Further studies are necessary to investigate whether this results from differences in patient characteristics, optimized patient selection, or refined choice of target vessel.

Protective effects of 5(S)-5-carboxystrictosidine on myocardial ischemia-reperfusion injury through activation of mitochondrial KATP channels

5(S)-5-carboxystrictosidine (5-CS) is a compound found in Mappianthus iodoides Hand.-Mazz., root, a traditional Chinese medicine used for the treatment of coronary artery disease. In this study, we investigated whether 5-CS protects heart against I/R injury. Sprague-Dawley rats were treated with 5-CS intraperitoneally for 7 days before the experiment. Hearts were perfused for 20 min global ischemia and 180 min reperfusion. 5-CS significantly inhibited an increase in the post-ischemic left ventricular end-diastolic pressure (LVEDP) and improved the post-ischemic left ventricular developed pressure (LVDP), dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow as compared with sham group. Pretreatment with 5-hydroxydecanoic acid (5-HD), an inhibitor of mitochondrial K_ATP channel, for 10 min before ischemia attenuated the improvement of LVEDP, LVDP, dP/dt maximum and dP/dt minimum rates of pressure change, and coronary flow induced by 5-CS. 5-CS markedly decreased the infarct size and attenuated the increased lactate dehydrogenase (LDH) level in effluent during reperfusion. Pretreatment with 5-HD also blocked these protective effects of 5-CS. 5-CS increased Mn-SOD, catalase, and HO-1 levels decreased by I/R injury and pretreatment of 5-HD blocked the 5-CS effects. Increases in Bax, cleaved caspase-3 and cytochrome c levels, caspase-3 and caspase-9 activity, and decrease in Bcl-2 level by I/R injury were attenuated by 5-CS treatment and pretreatment of 5-HD blocked its effects. These results suggest that the protective effects of 5-CS against myocardial I/R injury may be partly related to activating antioxidant enzymes and suppressing apoptosis through opening mitochondrial K_ATP channels.

Functional Angioplasty: Definitions, Historical Overview, and Future Perspectives

Percutaneous coronary intervention (PCI) is used to treat obstructive coronary artery disease (CAD). The role of PCI is well defined in acute coronary syndrome, but that for stable CAD remains debatable. Although PCI generally relieves angina in patients with stable CAD, it may not change its prognosis. The extent and severity of CAD are major determinants of prognosis, and complete revascularization (CR) of all ischemia-causing lesions might improve outcomes. Several studies have shown better outcomes with CR than with incomplete revascularization, emphasizing the importance of functional angioplasty. However, different definitions of inducible myocardial ischemia have been used across studies, making their comparison difficult. Various diagnostic tools have been used to estimate the presence, extent, and severity of inducible myocardial ischemia. However, to date, there are no agreed reference standards of inducible myocardial ischemia. The hallmarks of inducible myocardial ischemia such as electrocardiographic changes and regional wall motion abnormalities may be more clinically relevant as the reference standard to define ischemia-causing lesions. In this review, we summarize studies regarding myocardial ischemia, PCI guidance, and possible explanations for similar findings across studies. Also, we provide some insights into the ideal definition of inducible myocardial ischemia and highlight the appropriate PCI strategy.

Coronary Revascularization and Long-Term Survivorship in Chronic Coronary Syndrome

Ischemic heart disease (IHD) persists as the leading cause of death in the Western world. In recent decades, great headway has been made in reducing mortality due to IHD, based around secondary prevention. The advent of coronary revascularization techniques, first coronary artery bypass grafting (CABG) surgery in the 1960s and then percutaneous coronary intervention (PCI) in the 1970s, has represented one of the major breakthroughs in medicine during the last century. The benefit provided by these techniques, especially PCI, has been crucial in lowering mortality rates in acute coronary syndrome (ACS). However, in the setting where IHD is most prevalent, namely chronic coronary syndrome (CCS), the increase in life expectancy provided by coronary revascularization is controversial. Over more than 40 years, several clinical trials have been carried out comparing optimal medical treatment (OMT) alone with a strategy of routine coronary revascularization on top of OMT. Beyond a certain degree of symptomatic improvement and lower incidence of minor events, routine invasive management has not demonstrated a convincing effect in terms of reducing mortality in CCS. Based on the accumulated evidence more than half a century after the first revascularization procedures were used, invasive management should be considered in those patients with uncontrolled symptoms despite OMT or high-risk features related to left ventricular function, coronary anatomy, or functional assessment, taking into account the patient expectations and preferences.

A Novel Clinical and Stress Cardiac Magnetic Resonance (C-CMR-10) Score to Predict Long-Term All-Cause Mortality in Patients with Known or Suspected Chronic Coronary Syndrome

Vasodilator stress cardiac magnetic resonance (stressCMR) has shown robust diagnostic and prognostic value in patients with known or suspected chronic coronary syndrome (CCS). However, it is unknown whether integration of stressCMR with clinical variables in a simple clinical-imaging score can straightforwardly predict all-cause mortality in this population. We included 6187 patients in a large registry that underwent stressCMR for known or suspected CCS. Several clinical and stressCMR variables were collected, such as left ventricular ejection fraction (LVEF) and ischemic burden (number of segments with stress-induced perfusion defects (PD)). During a median follow-up of 5.56 years, we registered 682 (11%) all-cause deaths. The only independent predictors of all-cause mortality in multivariable analysis were age, male sex, diabetes mellitus (DM), LVEF and ischemic burden. Based on the weight of the chi-square increase at each step of the multivariable analysis, we created a simple clinical-stressCMR (C-CMR-10) score that included these variables (age ≥ 65 years = 3 points, LVEF ≤ 50% = 3 points, DM = 2 points, male sex = 1 point, and ischemic burden > 5 segments = 1 point). This 0 to 10 points C-CMR-10 score showed good performance to predict all-cause annualized mortality rate ranging from 0.29%/year (score = 0) to >4.6%/year (score ≥ 7). The goodness of the model and of the C-CMR-10 score was separately confirmed in 2 internal cohorts (n > 3000 each). We conclude that a novel and simple clinical-stressCMR score, which includes clinical and stressCMR variables, can provide robust prediction of the risk of long-term all-cause mortality in a population of patients with known or suspected CCS.