The Emerging Role of Drug-Induced Sleep Endoscopy in the Management of Obstructive Sleep Apnea

Obstructive sleep apnea is a prevalent sleep disorder characterized by partial or complete obstruction of the upper airway. Continuous positive airway pressure is the first-line therapy for most patients, but adherence is often poor. Alternative treatment options such as mandibular advancement devices, positional therapy, and surgical interventions including upper airway stimulation target different levels and patterns of obstruction with varying degrees of success. Drug-induced sleep endoscopy enables the visualization of upper airway obstruction under conditions mimicking sleep. In the era of precision medicine, this additional information may facilitate better decision-making when prescribing alternative treatment modalities, with the hope of achieving better adherence and/or success rates. This review discusses the current knowledge and evidence on the role of drug-induced sleep endoscopy in the non-positive airway pressure management of obstructive sleep apnea.

The Emerging Role of Drug-Induced Sleep Endoscopy in the Management of Obstructive Sleep Apnea

Obstructive sleep apnea is a prevalent sleep disorder characterized by partial or complete obstruction of the upper airway. Continuous positive airway pressure is the first-line therapy for most patients, but adherence is often poor. Alternative treatment options such as mandibular advancement devices, positional therapy, and surgical interventions including upper airway stimulation target different levels and patterns of obstruction with varying degrees of success. Drug-induced sleep endoscopy enables the visualization of upper airway obstruction under conditions mimicking sleep. In the era of precision medicine, this additional information may facilitate better decision-making when prescribing alternative treatment modalities, with the hope of achieving better adherence and/or success rates. This review discusses the current knowledge and evidence on the role of drug-induced sleep endoscopy in the non-positive airway pressure management of obstructive sleep apnea.

High-grade culprit lesions are a common cause of ST-segment elevation myocardial infarction

<p><b>INTRODUCTION</b>Conventional knowledge holds that the majority of ruptured atherosclerotic plaques causing ST-segment elevation myocardial infarction (STEMI) are found in moderate stenoses that produce < 50% loss of arterial diameter. This study aimed to analyse the culprit lesions in patients who presented with STEMI and underwent primary percutaneous coronary intervention (PPCI) at our institution.</p><p><b>METHODS</b>Patients who underwent PPCI between June 2008 and August 2010 at our institution were included in the analysis. Quantitative coronary angiography was performed for the culprit lesions immediately after antegrade flow was restored by thrombectomy, low-profile balloon predilatation or guidewire crossing.</p><p><b>RESULTS</b>A total of 1,021 patients were included in the study. The mean age was 57 ± 12 years and 85.2% were male. Lesion measurement was done after coronary flow was restored by thrombectomy (73.1%), balloon dilatation (24.1%) and following guidewire passage across the lesion (2.8%). Mean minimal luminal diameter was 1.1 ± 0.5 mm, mean reference vessel diameter was 2.8 ± 0.6 mm, mean diameter stenosis was 61 ± 16% and mean lesion length was 16 ± 6 mm. Most (80.2%) of the culprit lesions had diameter stenoses > 50% (p < 0.01). Although balloon angioplasty was performed in 24.1% of the patients, the majority (64.2%) still had diameter stenoses > 50%. High-grade stenoses (> 50%) were more frequently observed in male patients (p = 0.04).</p><p><b>CONCLUSION</b>Contrary to the existing paradigm, we found that most of the patients with STEMI in our institution had culprit lesions with diameter stenosis > 50%.</p>

Long-term Outcomes of Medical Therapy Versus Coronary Revascularisation in Patients with Intermediate Stenoses Guided by Pressure Wire

<p><b>INTRODUCTION</b>This study aimed to examine the long-term clinical outcomes of coronary fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) in a real-world population in an Asian tertiary centre.</p><p><b>MATERIALS AND METHODS</b>All patients who underwent FFR measurement for intermediate coronary lesions in our centre from June 2002 to December 2009 were enrolled. A threshold of FFR ≤0.75 was used for revascularisation. All the patients were prospectively followed-up for major adverse cardiac events (MACE) of death, myocardial infarction (MI), target vessel revascularisation (TVR) and stent thrombosis.</p><p><b>RESULTS</b>Based on FFR measurement, 368 (57%) patients were treated medically while 278 (43%) underwent revascularisation. At a mean follow-up duration of 29.7 ± 16 months, 53 (14.4%) patients in the medical therapy group and 32 (11.5%) patients in the revascularised group experienced MACE (P = 0.282). There were no statistical differences in all the clinical endpoints between the 2 groups.</p><p><b>CONCLUSION</b>Medical therapy based on FFR measurement is associated with low incidences of MACE at long-term follow-up.</p>

Pulmonary embolism as a cause of unexplained sinus tachycardia after right ventricular myocardial infarction

We present the case of a patient who developed new-onset asymptomatic sinus tachycardia after undergoing treatment for a right ventricular myocardial infarction. Even after excluding heart failure, infection and bleeding, the sinus tachycardia persisted. Computed tomography pulmonary angiography showed multiple bilateral pulmonary emboli. The vital sign abnormality resolved after treatment with an anticoagulant. We postulate that the pulmonary emboli originated from thrombi that were formed in the infarcted and dysfunctional right ventricle. Pulmonary embolism is a very rare complication of right ventricular myocardial infarction, and patients usually present with pleuritic chest pain. Our case highlights that asymptomatic sinus tachycardia could be a presenting feature of pulmonary embolism after the occurrence of a right ventricular myocardial infarction. A high index of suspicion is warranted in order to detect this potentially lethal complication.

Reperfusion strategy and mortality in ST-elevation myocardial infarction among patients with and without impaired renal function

<p><b>INTRODUCTION</b>Several randomised controlled trials have demonstrated better outcomes with primary percutaneous coronary intervention (PCI) over fibrinolytic therapy in the treatment of patients with ST-segment elevation myocardial infarction (STEMI) and normal renal function. Whether this benefit extends to patients with impaired renal function is uncertain.</p><p><b>MATERIALS AND METHODS</b>We studied 1672 patients with STEMI within 12 hours of symptom onset who were admitted to 2 major public hospitals in Singapore from 2000 to 2002. All patients received either upfront fibrinolytic or PCI as determined by the attending cardiologist. Serum creatinine was measured on admission and the glomerular filtration rate (GFR) was determined using the Modification of Diet in Renal Disease equation. The impact of reperfusion strategy on 30-ay mortality was then determined for patients with GFR > or =60 mL min-(1) 1.73 m-(2) and GFR <60 mL min-(1) 1.73 m-(2).</p><p><b>RESULTS</b>The mean age was 56 +/- 12 years (85% male) and mean GFR was 81 +/- 30 mL min-(1) 1.73 m-(2). Unadjusted 30-day mortality rates for fibrinolytic-treated vs primary PCI-treated patients were 29.4% vs 17.9%, P <0.05, in the impaired renal function group and 5.4% vs 3.1%, P <0.05, in the normal renal function group. After adjusting for covariates, primary PCI was associated with a significantly lower mortality in the normal renal function group [odds ratio (OR), 0.41; 95% confidence interval (CI), 0.19-0.89] but not in the impaired renal function group [OR, 0.70; 95% CI, 0.31-1.60].</p><p><b>CONCLUSIONS</b>Primary PCI was associated with improved 30-day survival among patients with normal renal function but not among those with impaired renal function. Randomised trials are needed to study the relative efficacy of both reperfusion strategies in patients with impaired renal function.</p>

Acute myocardial infarction in pregnant women

Acute myocardial infarction (AMI) in pregnant women is a rare but potentially lethal occurrence that should be carefully managed, especially in consideration of cardiac conditions being a rising cause of maternal deaths. Risk factors for AMI occurrence, in addition to typical cardiac-related risk factors, include medical conditions such as (pre) eclampsia, blood transfusions, thrombophilia and postpartum infections. Being older, multigravida or in the third trimester of pregnancy is also associated with an increased risk. The pathophysiological causes underlying AMI in pregnancy are diverse but generally associated with the coagulative and physiological changes related to the pregnancy. The selection of diagnostic modality and treatment options require careful consideration for pregnancy-related changes as well as risk of harm to the patient and fetus. This paper serves to review available literature regarding an extensive range of management issues that directly impact on maternal and fetal outcomes.