Predictive value of ST resolution analysis performed immediately versus at ninety minutes after primary percutaneous coronary intervention

Role of ST-Segment Resolution Alone and in Combination With TIMI Flow After Primary Percutaneous Coronary Intervention for ST-Segment-Elevation Myocardial Infarction

Background To evaluate the role of ST-segment resolution (STR) alone and in combination with Thrombolysis in Myocardial Infarction (TIMI) flow in reperfusion evaluation after primary percutaneous coronary intervention (PPCI) for ST-segment-elevation myocardial infarction by investigating the long-term prognostic impact. Methods and Results From January 2013 through September 2014, we studied 5966 patients with ST-segment-elevation myocardial infarction enrolled in the CAMI (China Acute Myocardial Infarction) registry with available data of STR evaluated at 120 minutes after PPCI. Successful STR included STR ≥50% and complete STR (ST-segment back to the equipotential line). After PPCI, the TIMI flow was assessed. The primary outcome was 2-year all-cause mortality. STR < 50%, STR ≥50%, and complete STR occurred in 20.6%, 64.3%, and 15.1% of patients, respectively. By multivariable analysis, STR ≥50% (5.6%; adjusted hazard ratio [HR], 0.45 [95% CI, 0.36-0.56]) and complete STR (5.1%; adjusted HR, 0.48 [95% CI, 0.34-0.67]) were significantly associated with lower 2-year mortality than STR <50% (11.7%). Successful STR was an independent predictor of 2-year mortality across the spectrum of clinical variables. After combining TIMI flow with STR, different 2-year mortality was observed in subgroups, with the lowest in successful STR and TIMI 3 flow, intermediate when either of these measures was reduced, and highest when both were abnormal. Conclusions Post-PPCI STR is a robust long-term prognosticator for ST-segment-elevation myocardial infarction, whereas the integrated analysis of STR plus TIMI flow yields incremental prognostic information beyond either measure alone, supporting it as a convenient and reliable surrogate end point for defining successful PPCI. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01874691.

Assessment of Selected Baseline and Post-PCI Electrocardiographic Parameters as Predictors of Left Ventricular Systolic Dysfunction after a First ST-Segment Elevation Myocardial Infarction

OBJECTIVE

To assess the performance of ten electrocardiographic (ECG) parameters regarding the prediction of left ventricular systolic dysfunction (LVSD) after a first ST-segment-elevation myocardial infarction (STEMI).

METHODS

We analyzed 249 patients (74.7% males) treated with primary percutaneous coronary intervention (PCI) included into a single-center cohort study. We sought associations between baseline and post-PCI ECG parameters and the presence of LVSD (defined as left ventricular ejection fraction [LVEF] ≤ 40% on echocardiography) 6 months after STEMI.

RESULTS

Patients presenting with LVSD (n = 52) had significantly higher values of heart rate, number of leads with ST-segment elevation and pathological Q-waves, as well as total and maximal ST-segment elevation at baseline and directly after PCI compared with patients without LVSD. They also showed a significantly higher prevalence of anterior STEMI and considerably wider QRS complex after PCI, while QRS duration measurement at baseline showed no significant difference. Additionally, patients presenting with LVSD after 6 months showed markedly more severe ischemia on admission, as assessed with the Sclarovsky-Birnbaum ischemia score, smaller reciprocal ST-segment depression at baseline and less profound ST-segment resolution post PCI. In multivariate regression analysis adjusted for demographic, clinical, biochemical and angiographic variables, anterior location of STEMI (OR 17.78; 95% CI 6.45-48.96; p < 0.001), post-PCI QRS duration (OR 1.56; 95% CI 1.22-2.00; p < 0.001) expressed per increments of 10 ms and impaired post-PCI flow in the infarct-related artery (IRA; TIMI 3 vs. <3; OR 0.14; 95% CI 0.04-0.46; p = 0.001) were identified as independent predictors of LVSD (Nagelkerke's pseudo R2 for the logistic regression model = 0.462). Similarly, in multiple regression analysis, anterior location of STEMI, wider post-PCI QRS, higher baseline number of pathological Q-waves and a higher baseline Sclarovsky-Birnbaum ischemia score, together with impaired post-PCI flow in the IRA, higher values of body mass index and glucose concentration on admission were independently associated with lower values of LVEF at 6 months (corrected R2 = 0.448; p < 0.00001).

CONCLUSIONS

According to our study, baseline and post-PCI ECG parameters are of modest value for the prediction of LVSD occurrence 6 months after a first STEMI.

Mechanistic Role of mPTP in Ischemia-Reperfusion Injury

Acute myocardial infarction (MI) is a major cause of death and disability worldwide. The treatment of choice for reducing ischemic injury and limiting infarct size (IS) in patients with ST-segment elevation MI (STEMI) is timely and effective myocardial reperfusion via primary percutaneous coronary intervention (PCI). However, myocardial reperfusion itself may induce further cardiomyocyte death, a phenomenon known as reperfusion injury (RI). The opening of a large pore in the mitochondrial membrane, namely, the mitochondrial permeability transition pore (mPTP), is widely recognized as the final step of RI and is responsible for mitochondrial and cardiomyocyte death. Although myocardial reperfusion interventions continue to improve, there remain no effective therapies for preventing RI due to incomplete knowledge regarding RI components and mechanisms and to premature translations of findings from animals to humans. In the last year, increasing amounts of data describing mPTP components, structure, regulation and function have surfaced. These data may be crucial for gaining a better understanding of RI genesis and for planning future trials evaluating new cardioprotective strategies. In this chapter, we review the role of the mPTP in RI pathophysiology and report on recent studies investigating its structure and components. Finally, we provide a brief overview of principal cardioprotective strategies and their pitfalls.

Impact of obstructive sleep apnea on myocardial tissue perfusion in patients with ST-segment elevation myocardial infarction

BACKGROUND

Vascular endothelial dysfunction has been recognized as an essential feature of obstructive sleep apnea (OSA). This study was designed to examine the hypothesis that OSA may impair the coronary microcirculation in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS AND RESULTS

The present study included 100 patients with a first STEMI who underwent primary percutaneous coronary intervention (PCI) within 12h from onset. Coronary flow velocity at baseline and at maximum hyperemia was measured using a Doppler guidewire following PCI. Total ST-segment elevation was calculated at baseline and 30 min after PCI. All patients underwent polysomnography at 14 days to diagnose OSA. Coronary flow velocity reserve (CFVR) was used for quantitative analysis of myocardial tissue perfusion. Systolic retrograde flow (SRF) and ST-segment resolution (STR) <50% were used as an index of microvascular injury. Forty-eight patients presented with OSA. CFVR was comparable between the 2 groups. The incidence of SRF was higher in OSA patients than in the control patients (6% vs. 31%, P=0.005). Patients with OSA had a higher incidence of STR <50% (31% vs. 60%, P=0.003). Multiple logistic regression showed that OSA was an independent positive predictor of SRF and STR <50% (odds ratio=4.46, P=0.044; odds ratio=3.79, P=0.010).

CONCLUSIONS

OSA may impair myocardial tissue perfusion following primary PCI.