Adrian F. Low

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.

Absorb Bioresorbable Vascular Scaffold Versus Everolimus-Eluting Metallic Stent in ST-Segment Elevation Myocardial Infarction: 1-Year Results of a Propensity Score Matching Comparison: The BVS-EXAMINATION Study (Bioresorbable Vascular Scaffold-A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-segment Elevation Myocardial Infarction)

OBJECTIVES The purpose of this study was to compare the 1-year outcome between bioresorbable vascular scaffold (BVS) and everolimus-eluting metallic stent (EES) in ST-segment elevation myocardial infarction (STEMI) patients. BACKGROUND The Absorb BVS (Abbott Vascular, Santa Clara, California) is a polymeric scaffold approved for treatment of stable coronary lesions. Limited and not randomized data are available on its use in ST-segment elevation myocardial infarction (STEMI) patients. METHODS This study included 290 consecutive STEMI patients treated by BVS, compared with either 290 STEMI patients treated with EES or 290 STEMI patients treated with bare-metal stents (BMS) from the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-segment Elevation Myocardial Infarction) trial, by applying propensity score matching. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization, at 1-year follow-up. Device thrombosis, according to the Academic Research Consortium criteria, was also evaluated. RESULTS The cumulative incidence of DOCE did not differ between the BVS and EES or BMS groups either at 30 days (3.1% vs. 2.4%, hazard ratio [HR]: 1.31 [95% confidence interval (CI): 0.48 to 3.52], p = 0.593; vs. 2.8%, HR: 1.15 [95% CI: 0.44 to 2.30], p = 0.776, respectively) or at 1 year (4.1% vs. 4.1%, HR: 0.99 [95% CI: 0.23 to 4.32], p = 0.994; vs. 5.9%, HR: 0.50 [95% CI: 0.13 to 1.88], p = 0.306, respectively). Definite/probable BVS thrombosis rate was numerically higher either at 30 days (2.1% vs. 0.3%, p = 0.059; vs. 1.0%, p = 0.324, respectively) or at 1 year (2.4% vs. 1.4%, p = 0.948; vs. 1.7%, p = 0.825, respectively), as compared with EES or BMS. CONCLUSIONS At 1-year follow-up, STEMI patients treated with BVS showed similar rates of DOCE compared with STEMI patients treated with EES or BMS, although rate of scaffolds thrombosis, mostly clustered in the early phase, was not negligible. Larger studies with longer follow-up are needed to confirm our findings.

Growth differentiation factor 15, ST2, high‐sensitivity troponin T, and N‐terminal pro brain natriuretic peptide in heart failure with preserved vs. reduced ejection fraction

Growth differentiation factor 15 (GDF15), ST2, high‐sensitivity troponin T (hsTnT), and N‐terminal pro brain natriuretic peptide (NT‐proBNP) are biomarkers of distinct mechanisms that may contribute to the pathophysiology of heart failure (HF) [inflammation (GDF15); ventricular remodelling (ST2); myonecrosis (hsTnT); and wall stress (NT‐proBNP)].

New Set of Intravascular Ultrasound-Derived Anatomic Criteria for Defining Functionally Significant Stenoses in Small Coronary Arteries (Results from Intravascular Ultrasound Diagnostic Evaluation of Atherosclerosis in Singapore (IDEAS) Study)

We sought to determine the intravascular ultrasound-derived anatomic criteria for functionally significant lesions in small coronary arteries with a reference segment diameter <3 mm. A fractional flow reserve (FFR) of <0.75, as determined by pressure wire using high-dose (100 to 150 microg) intracoronary adenosine, was used as the reference standard for functional significance. For the 94 patients/lesions involved in the present study, the average reference vessel diameter was 2.72 mm. The FFR was <0.75 in 38 patients (40.4%) and > or =0.75 in 56 patients (59.6%). Logistic regression analysis identified the minimal lumen area, plaque burden, and lesion length as the 3 most important determinants of the FFR. Using classification and regression tree analysis, the best cutoff values for these determinants to discriminate a FFR of <0.75 versus > or =0.75 were a minimal lumen area of < or =2.0 mm(2) (sensitivity 82.35%, specificity 80.77%), plaque burden of > or =80% (sensitivity 87.9%, specificity 78.9%), and lesion length of > or =20 mm (sensitivity 63.6%, specificity 78.9%). A significant increase was found in the area under the receiver operating characteristic curve of the combined parameters (minimal lumen area plus plaque burden plus lesion length) compared to the plaque burden (p = 0.014) and other individual parameters (p <0.001). In conclusion, we found that intravascular ultrasound-derived anatomic criteria are able to predict the functional significance of intermediate lesions in small coronary arteries. A minimal lumen area of < or =2.0 mm(2), plaque burden of > or =80%, and lesion length of > or =20 mm predicted a FFR of <0.75 with good sensitivity and specificity.

Severe obstructive sleep apnea and outcomes following myocardial infarction.

STUDY OBJECTIVE We sought to determine the effect of severe obstructive sleep apnea (OSA) on long-term outcomes after myocardial infarction. We hypothesized that severe OSA was associated with lower event-free survival rate after ST-segment elevation myocardial infarction (STEMI). METHODS A total of 120 patients underwent an overnight sleep study during index admission for STEMI. Severe OSA was defined as apnea hypopnea index (AHI) ≥ 30, and non-severe OSA defined as AHI < 30. RESULTS Among the 105 patients who completed the study, 44 (42%) had severe OSA and 61 (58%) non-severe OSA. The median creatine kinase level and mean left ventricular systolic function were similar between the 2 groups. None of the 105 study patients had received treatments for OSA. Between 1- and 18-month follow-up, the severe OSA group incurred 1 death, 2 reinfarctions, 1 stroke, 6 unplanned target vessel revascularizations, and 1 heart failure hospitalization. In contrast, there were only 2 unplanned target vessel revascularizations in the non-severe OSA group. The incidence of major adverse events was significantly higher in the severe OSA group (15.9% versus 3.3%, adjusted hazard ratios: 5.36, 95% CI: 1.01 to 28.53, p = 0.049). Kaplan-Meier event-free survival curves showed the event-free survival rates in the severe OSA group was significantly worse than that in the non-severe OSA group (p = 0.021, log-rank test). CONCLUSION 42% of the patients admitted with STEMI have undiagnosed severe OSA. Severe OSA carries a negative prognostic impact for this group of patients. It is associated with a lower event-free survival rate at 18-month follow-up.

Growth differentiation factor 15 in heart failure with preserved vs. reduced ejection fraction.

Growth differentiation factor 15 (GDF15) is a cytokine highly expressed in states of inflammatory stress. We aimed to study the clinical correlates and prognostic significance of plasma GDF15 in heart failure with preserved ejection fraction (HFpEF) vs. reduced ejection fraction(HFrEF), compared with N‐terminal pro‐brain natriuretic peptide (NT‐proBNP), an indicator of haemodynamic wall stress.

Iron deficiency in a multi-ethnic Asian population with and without heart failure: prevalence, clinical correlates, functional significance and prognosis

Current heart failure (HF) guidelines highlight the importance of iron deficiency (ID) in HF. Whether HF itself or age‐related comorbidities contribute to ID is uncertain, and previous data were limited to Western populations. We aimed to study the prevalence, clinical correlates, functional significance and prognosis of ID in HF patients, compared with community‐based controls in a multi‐ethnic Southeast Asian population.

Endothelial progenitor cell capture stent implantation in patients with ST-segment elevation acute myocardial infarction: one year follow-up

AIMS The Genous endothelial progenitor cell (EPC) capture stent is a bioengineered R stent coated with immobilised antibodies on its stent struts to allow for the capture of circulating EPCs to promote rapid endothelisation. We assessed the impact of this stent in the primary percutaneous coronary intervention (PCI) of patients with acute ST-elevation myocardial infarction (STEMI) and examined its long term clinical outcomes. METHODS AND RESULTS All patients with acute STEMI without cardiogenic shock who underwent primary PCI between January 2005 and April 2007 and received the stent were enrolled in the study. The study endpoints were major adverse cardiac events (MACE) defined as death, MI and target vessel revascularisation (TVR) at 30 days, six months and one year. A total of 321 enrolled patients received 357 EPC capture stents during the study period. The cohort comprises 81.0% males with mean age of 54.6+/-11.6 years. The mean stent length used was 20.98+/-5.50 mm and mean stent size was 2.99+/-0.32 mm. Ninety-four percent of patients achieved Thrombolysis in Myocardial Infarction (TIMI) 3 flow post-procedurally. The cumulative MACE rate was 8.1% at 30 days, 10.0% at six months and 12.2% at one year. There was one patient who developed acute stent thrombosis and another two with subacute stent thromboses. No late thrombosis or late cardiac mortality was observed in our cohort. The need for TVR was 4.4% at one year. CONCLUSIONS The use of EPC capture stents in patients who underwent primary PCI for STEMI is safe and showed good clinical outcomes, with low rates of TVR and no late stent thrombosis.

Fulminant dengue myocarditis masquerading as acute myocardial infarction

Dengue fever is manifested by a sudden onset of fever (http://en.wikipedia.org/wiki/Fever), with severe headache, myalgias (http://en.wikipedia.org/wiki/Myalgia), arthralgias (http://en.wikipedia.org/wiki/Arthralgia) and characteristic bright red petechia (http://en.wikipedia.org/wiki/Petechia). The exact incidence and pathophysiological mechanism of dengue myocarditis remain obscure, but most of these cases are self-limiting. Fatal dengue myocarditis is a very rare complication of dengue fever. The non-specific symptoms and signs of dengue myocarditis make early diagnosis difficult. A 25-year-old Indian male, suffered from fulminant dengue myocarditis, presented to a our hospital with symptoms and electrocardiographic features mimicking acute myocardial infarction. Unfortunately, the patient succumbed before the dengue serology results were available.

The Singapore Heart Failure Outcomes and Phenotypes (SHOP) Study and Prospective Evaluation of Outcome in Patients With Heart Failure With Preserved Left Ventricular Ejection Fraction (PEOPLE) Study: Rationale and Design

BACKGROUND Heart failure (HF) with preserved ejection fraction (EF) accounts for a substantial proportion of cases of HF, and to date no treatments have clearly improved outcome. There are also little data comparing HF cohorts of differing ethnicity within the Asia-Pacific region. METHODS The Singapore Heart Failure Outcomes and Phenotypes (SHOP) study and Prospective Evaluation of Outcome in Patients with Heart Failure with Preserved Left Ventricular Ejection Fraction (PEOPLE) study are parallel prospective studies using identical protocols to enroll patients with HF across 6 centers in Singapore and 4 in New Zealand. The objectives are to determine the relative prevalence, characteristics, and outcomes of patients with HF and preserved EF (EF ≥50%) compared with those with HF and reduced EF, and to determine initial data on ethnic differences within and between New Zealand and Singapore. Case subjects (n = 2,500) are patients hospitalized with a primary diagnosis of HF or attending outpatient clinics for management of HF within 6 months of HF decompensation. Control subjects are age- and gender-matched community-based adults without HF from Singapore (n = 1,250) and New Zealand (n = 1,073). All participants undergo detailed clinical assessment, echocardiography, and blood biomarker measurements at baseline, 6 weeks, and 6 months, and are followed over 2 years for death or hospitalization. Substudies include vascular assessment, cardiopulmonary exercise testing, retinal imaging, and cardiac magnetic resonance imaging. CONCLUSIONS The SHOP and PEOPLE studies are the first prospective multicenter studies defining the epidemiology and interethnic differences among patients with HF in the Asia-Oceanic region, and will provide unique insights into the pathophysiology and outcomes for these patients.