Eric Chong

Obstructive Sleep Apnea in Patients Admitted for Acute Myocardial Infarction: Prevalence, Predictors, and Effect on Microvascular Perfusion

BACKGROUND We investigated the prevalence and predictors of obstructive sleep apnea (OSA) in patients admitted to the hospital for acute myocardial infarction and whether OSA has any association with microvascular perfusion after primary percutaneous coronary intervention (PCI). METHODS Recruited patients were scheduled to undergo an overnight sleep study between 2 and 5 days after primary PCI. An apnea-hypopnea index (AHI) of > or = 15 was considered diagnostic of OSA. Impaired microvascular perfusion after primary PCI was defined as an ST-segment resolution of < or = 70%, myocardial blush grade 0 or 1, or a corrected Thrombolysis in Myocardial Infarction (TIMI) [antegrade flow scale] frame count > 28. RESULTS Sleep study was performed in 120 patients and completed in 105 patients (study cohort, mean age 53 +/- 10 years, male 98%) with uncomplicated myocardial infarction. An AHI was > or = 15 in 69 patients (OSA-positive), giving a prevalence of 65.7%. Diabetes mellitus was found to be a significant risk factor for OSA (odds ratio, 2.86; 95% confidence interval, 1.06 to 8.24; p = 0.033). There were no differences between OSA-positive and OSA-negative groups with regard to the percentage of patients with < or = 70% ST-segment resolution (73% vs 64%, respectively; p = 0.411), myocardial blush grade 0 or 1 (39.1% vs 38.9%, respectively; p = 1.000), or corrected TIMI frame count > 28 (21.7% vs 25.0%, respectively; p = 0.807). CONCLUSIONS We found a high prevalence of previously undiagnosed OSA in patients admitted with acute myocardial infarction. Diabetes mellitus was independently associated with OSA. No evidence indicated that OSA is associated with impaired microvascular perfusion after primary PCI.

Effectiveness and Safety of the Genous Endothelial Progenitor Cell-Capture Stent in Acute ST-Elevation Myocardial Infarction

The endothelial progenitor cell (EPC)-capture stent promotes endothelialization and preliminary studies have suggested its safety and feasibility in ST-elevation myocardial infarction (STEMI). Detailed late clinical follow-up and angiographic analyses are, however, limited. We sought to determine late angiographic and clinical outcomes of the Genous EPC-capture stent in primary angioplasty. EPC-capture stents were implanted during primary angioplasty in 489 consecutive patients presenting with STEMI from 2004 through 2008. The first 100 consenting patients undergoing successful stent implantation scheduled to undergo relook coronary angiography at 6 to 12 months were enrolled. Ninety-five patients with 96 lesions were analyzed independently. Mean duration of follow-up coronary angiography was 245 days. In-stent late luminal loss measured 0.87 ± 0.67 mm. Binary restenosis (defined as >50% diameter stenosis) was 28%, with diffuse in-stent restenosis (Mehran class II) as the predominant pattern. Of 27 patients with binary restenosis, 14 (52%) were symptomatic, with 10 patients undergoing target lesion revascularization. Asymptomatic patients had significantly larger reference vessel and in-stent minimal luminal diameters (2.77 ± 0.39 vs 2.54 ± 0.44 mm, p = 0.040; 2.74 ± 0.34 vs 2.31 ± 0.72 mm, p = 0.004, respectively). Follow-up late loss and diameter stenoses were also in favor of the asymptomatic group. Major adverse cardiac event rate was 16% at a mean follow-up of 34 months. There were no cases of Academic Research Consortium-defined stent thrombosis. In conclusion, implantation of the EPC-capture stent during primary angioplasty is associated with a favorable late clinical outcome but with higher than anticipated angiographic late loss.

Reperfusion therapies reduce ischemic mitral regurgitation following inferoposterior ST-segment elevation myocardial infarction.

BackgroundThe presence of ischemic mitral regurgitation (IMR) after ST-segment elevation myocardial infarction (STEMI) portends a poorer prognosis. The possible influence of reperfusion therapy in restoring mitral valve competence in inferoposterior STEMI has not been well elucidated. Methods and resultsWe studied 423 consecutive patients with a first inferoposterior STEMI and determined the presence of IMR in patients treated with reperfusion therapy versus medical therapy. A primary percutaneous coronary intervention (PCI) was performed in 186 patients; 74 patients underwent thrombolysis, 63 patients had rescue PCI whereas 54 patients were treated medically. The mean time interval between STEMI presentation and echocardiography was 14±27 days. Patients receiving reperfusion therapy had less moderate or severe IMR (2.5 vs. 11.1%, P=0.001). The presence of IMR between the primary PCI and the thrombolytic groups was similar (52.2 vs. 60.8%, P=NS). Left ventricular ejection fraction (47.7±10.3 vs. 53.1±11.4%, P<0.001) and infarct size (mean CK-MB) (271±168 vs. 222±151 U/l, P<0.001) were significantly worse in patients with IMR. Dominance of the coronary artery system, involvement of the right or the left coronary arteries, and the presence of triple-vessel disease did not correlate with the presence of IMR. After adjustment for age and left ventricular ejection fraction, there was a trend toward poorer survival and recurrent admission for heart failure at 1 year in patients with IMR (hazard ratio=2.4, 95% confidence interval 0.91–6.2, P=0.08). ConclusionBoth thrombolytic therapy and primary PCI were associated with decreased incidences of IMR following inferoposterior STEMI.