The utility of perioperative polygraphy in the diagnosis of obstructive sleep apnea.

OBJECTIVE/BACKGROUND: Obstructive sleep apnea (OSA) is highly prevalent and often undiagnosed in surgical patients. The aim of this study was to compare polygraphy (PG) performed on sedated patients during surgery to overnight polysomnography (PSG). It was hypothesized that perioperative PG may be used to diagnose OSA. PATIENTS/METHODS: Overnight PSG was performed three days prior to surgery. For surgery, spinal anesthesia and sedation with propofol infusion were used. Sedation depth was monitored by the Bispectral index and maintained for all patients (target level 75). Echocardiography studies were available in three patients, and all were diagnosed with diastolic dysfunction. Relatively high prevalence of CSA in patients with diastolic dysfunction has been previously reported. During surgery, PG recording (Embletta) was performed. Sleep apnea was defined by the type (central/obstructive apnea ≥50%) and by the apnea-hypopnea index (AHI) (events/hour: AHI < 5 no apnea; 5 ≤ AHI < 15 mild apnea; 15 ≤ AHI < 30 moderate apnea; AHI ≥30 severe apnea). Bland-Altman plots were used for analysis, and 2 × 2 decision statistics were calculated for several cut-off values of the AHI. Data were shown as bias with limits of agreement (bias±1.96 standard deviations). RESULTS: Nineteen subjects were studied: nine (47%) were diagnosed with obstructive, seven (37%) with central sleep apnea, and three (16%) with no sleep apnea by overnight PSG. Perioperative PG bias was 12 (-37; 61) for AHI; 6 (-25; 37) for obstructive apnea; 0 (-4; 4) for central apnea, and 6 (-31; 43) for hypopnea. For the detection of OSA, a PG cut-off value of AHI 5 yielded 89% sensitivity and 60% specificity, AHI 15 yielded 86% sensitivity and 67% specificity, and AHI 30 yielded 100% sensitivity and 71% specificity. CONCLUSION: Wide limits of agreement preclude perioperative PG to be used as a diagnostic method; however, it may be useful to screen sedated surgical patients for OSA.

Comparison of sublingual isosorbide dinitrate and Valsalva maneuver for detection of obstruction in hypertrophic cardiomyopathy.

INTRODUCTION: A left ventricular outflow tract (LVOT) obstruction assessment with a provoking test should be a routine part of the evaluation of patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to compare the utility of the Valsalva maneuver (VM) and sublingual spray application of isosorbide dinitrate (ISDN) for detection of an obstruction. MATERIAL AND METHODS: We prospectively evaluated 81 consecutive HCM patients without severe rest LVOT obstruction (defined as peak rest pressure gradient (PG) ≥ 50 mm Hg). We measured PG at rest, during the VM, after sublingual ISDN spray, and during the VM after ISDN. An obstruction was defined as a PG ≥ 30 mm Hg. RESULTS: An obstruction was present in 15 patients (19%) at rest (median and interquartile range of PG 16 (7-26) mm Hg), in 38 patients (47%) during the VM (PG 28 (12-49) mm Hg), in 50 (62%) patients after ISDN (PG 50 (12-79) mm Hg), and in 55 patients (68%) during the VM after ISDN (PG 59 (20-87) mm Hg). The difference in occurrence of obstruction among different provoking tests was statistically significant for all comparisons (p < 0.001, except for the comparison of the ISDN test with the VM during ISDN, p = 0.025). CONCLUSIONS: The ISDN test and the VM are useful screening methods for the detection of an HCM obstruction. Although ISDN appears to be more precise than the VM, the best option is a combination of both methods, which maximizes inducement of LVOT obstruction in patients with HCM.

Sleep apnea prevalence in acute myocardial infarction--the Sleep Apnea in Post-acute Myocardial Infarction Patients (SAPAMI) Study.

BACKGROUND: While sleep apnea (SA) might be a modifiable cardiovascular risk factor, recent data suggest that SA is severely underdiagnosed in patients after acute myocardial infarction (MI). There is limited evidence about day-night variation of onset of MI on dependence of having SA. We therefore investigated the prevalence of SA and examined the day-night variation of onset of MI in acute MI patients. METHODS: We prospectively studied 782 consecutive patients admitted to the hospital with the diagnosis of acute MI. All subjects underwent sleep evaluations using a portable device after at least 48 h post-admission. Using the apnea-hypopnea index (AHI), groups were defined as patients without SA (<5 events/h), mild SA (5-15 events/h), moderate SA (15-30 events/h), and severe SA (≥ 30 events/h). RESULTS: Almost all patients (98%) underwent urgent coronary angiography and 91% of patients underwent primary PCI. Using a threshold of AHI ≥ 5 events/h, SA was present in 65.7% of patients after acute MI. Mild SA was present in 32.6%, moderate in 20.4% and severe in 12.7%. The day-night variation in the onset of MI in all groups of SA patients was similar to that observed in non-SA patients. From 6 AM to 12 PM, the frequency of MI was higher in both SA and non-SA patients, as compared to the interval from 12 AM to 6 AM (all p<0.05). CONCLUSION: There is a high prevalence of SA in patients presenting with acute MI. Peak time of MI onset in SA patients was between 6 AM and noon, similar to that in the general population. Whether diagnosis and treatment of SA after MI will significantly improve outcomes in these patients remains to be determined.

Endovascular brain intervention and mapping in a dog experimental model using magnetically-guided micro-catheter technology.

AIM: Despite the substantial progress that has been achieved in interventional cardiology and cardiac electrophysiology, endovascular intervention for the diagnosis and treatment of central nervous system (CNS) disorders such as stroke, epilepsy and CNS malignancy is still limited, particularly due to highly tortuous nature of the cerebral arterial and venous system. Existing interventional devices and techniques enable only limited and complicated access especially into intra-cerebral vessels. The aim of this study was to develop a micro-catheter magnetically-guided technology specifically designed for endovascular intervention and mapping in deep CNS vascular structures. METHODS: Mapping of electrical brain activity was performed via the venous system on an animal dog model with the support of the NIOBE II system. RESULTS: A novel micro-catheter specially designed for endovascular interventions in the CNS, with the support of the NIOBE II technology, was able to reach safely deep intra-cerebral venous structures and map the electrical activity there. Such structures are not currently accessible using standard catheters. CONCLUSION: This is the first study demonstrating successful use of a new micro-catheter in combination with NIOBE II technology for endovascular intervention in the brain.