Subclinical and latent cardiac dysfunction in obstructive sleep apnea and effectiveness of continuous positive airway pressure

PURPOSE

Obstructive sleep apnea (OSA) is associated with various cardiovascular disorders. This study aimed to investigate the effects of OSA on left ventricular (LV) function in patients with OSA who were at risk for heart failure but who had not yet developed structural heart changes. The study also sought to determine the effects of continuous positive airway pressure (CPAP) in these patients.

METHODS

In a retrospective study, consecutive patients with polysomnographic OSA (apnea-hypopnea index [AHI] >5) were categorized into mild (AHI < 15), moderate (15 ≤ AHI < 30), and severe OSA (AHI ≥ 30) groups. The subjects were patients with OSA and at risk for heart failure who had not yet developed structural heart changes. All study participants underwent echocardiography and two-dimensional speckle tracking analysis, and their global longitudinal strain (GLS) was calculated.

RESULTS

Of 275 patients, there were 31 with mild, 92 with moderate, and 152 with severe OSA. Of patients with moderate to severe OSA (AHI ≥ 20), 206 started CPAP and 92 patients underwent follow-up echocardiogram and speckle tracking echo analysis (median period of CPAP use: 283 days [258 to 391]). GLS was significantly reduced in patients with moderate and severe OSA compared with mild OSA (-17.8±3.1 vs. -18.0±2.6 vs. -19.3±2.8%, p=0.038). The proportion of patients with GLS ≥ -18% was significantly higher among the patients with moderate to severe OSA than among those with mild OSA. GLS improved after CPAP therapy in patients with moderate to severe OSA (GLS: -18.1±2.7% to -19.0±2.8%, p=0.004). Significant improvement in GLS was confirmed, particularly among patients with good CPAP adherence.

CONCLUSION

Moderate to severe OSA is associated with LV dysfunction and can be significantly improved by CPAP therapy.

Acute Myocardial Infarction Due to Coronary Artery Embolism during Chemotherapy with mFOLFOX-6 Plus Bevacizumab for Metastatic Colon Cancer

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, may be associated with arterial embolisms. We herein report a case of acute myocardial infarction caused by coronary embolism during combination chemotherapy with mFOLFOX-6 and bevacizumab in a patient with metastatic colon cancer. Thromboembolism occurred only in the distal right posterolateral branch without stenotic lesions or plaque rupture in the proximal branch of the right coronary artery. Sole thromboaspiration was successfully performed; the final angiogram demonstrated no stenosis in the right coronary artery. Bevacizumab may be associated with acute coronary syndrome in patients with coronary risk factors, despite no significant coronary narrowing.

Emergency Transcatheter Aortic Valve Implantation in a Surgical Aortic Bioprosthetic Valve for Acute Decompensated Heart Failure Caused by Sudden Progression of Structural Valve Deterioration

Bioprosthetic aortic valves have limited durability. We herein report sudden progression of structural valve deterioration (SVD) and a successful case of emergency transcatheter aortic valve (TAV) implantation for acute decompensated heart failure (ADHF) caused by SVD. A 79-year-old man who had undergone a Bentall operation 11 years prior was diagnosed with ADHF due to suddenly progressive SVD. Emergency TAV implantation in the surgical bioprosthetic valve was selected based on the surgical risk. Ours and previous case reports suggest that SVD can progress suddenly, even after months of stability, and that emergency TAV implantation is effective.

Difficulty Diagnosing Retrograde Type A Aortic Dissection with Intramural Hematoma and Risk of Re-dissection and Rupture: A Report of Two Cases

Acute type A aortic dissection is a potentially fatal disease, and emergency surgery should be considered when it is diagnosed. We herein report two cases of retrograde type A aortic dissection with intramural hematoma, followed by re-dissection, rupture, and cardiac tamponade. The diagnoses in these cases had to be made carefully, as the false lumen of the ascending aorta was sometimes unclear on contrast-enhanced computed tomography.

The Diagnosis of Spontaneous Coronary Artery Dissection by Optical Coherence Tomography

Spontaneous coronary artery dissection (SCAD) is rare, but it frequently presents as acute myocardial infarction. It is frequently fatal and most cases are diagnosed at autopsy. We herein present the case of a 65-year-old woman with ST-elevation and myocardial infarction due to SCAD. Optical coherence tomography (OCT) helped us to confirm the diagnosis. The information on the intravascular morphology provided by OCT imaging is much more detailed in comparison to that provided by coronary angiography (CAG) and intravascular ultrasound (IVUS).

[A case of transient left ventricular ballooning ("Takotsubo"-shaped cardiomyopathy) developed during plasmapheresis for treatment of myasthenic crisis]

An 83-year-old woman was admitted to our hospital complaining of respiratory distress. She developed blepharoptosis and dysphagia two months previously. On admission, blood pressure was 150/84 mmHg. There were bilateral blepharoptosis and bulbar palsy. Tendon reflexes were brisk, but pathological reflexes were absent. Repetitive stimulation test demonstrated decrement. Tensilon test was positive. Thus, a diagnosis of myasthenic crisis was made. Vital capacity was 0.71, which necessitated intubation and artificial ventilation. During the first course of immunoadsorption plasmapheresis, blood pressure fell to 80/50 mmHg. ECG showed deeply inverted T waves in leads V2 through V6. Echocardiographic examination demonstrated extensive akinesis around the apex. CK was slightly increased. A diagnosis of "Takotsubo"-shaped cardiomyopathy was made. To maintain blood pressure, dopamine was continuously injected. Left ventricular function returned to normal within a week. No thymoma was seen on the chest CT scan. She was treated with pyridostigmine and tacrolimus. Ten weeks after admission, she was weaned off the ventilator and she had no dysphagia anymore. Anti-acetylcholine receptor antibody titers had decreased. In Japan, approximately 17% of patients with myasthenia gravis are in the seventh decade or older. Approximately 10% of the patients of this age group suffer from severe generalized form. Careful ECG monitoring is necessary while treating elderly patients with myasthenic crisis, because they are at potential risk of developing "Takotsubo"-shaped cardiomyopathy.

Usefulness of Stress Myocardial Perfusion Imaging for Evaluating Asymptomatic Patients After Coronary Stent Implantation

BACKGROUND

Stent implantation in coronary angioplasty has reduced the rate of restenosis, but many patients still undergo follow-up coronary angiography (CAG). The present study was a multi-center retrospective analysis of the usefulness of stress single photon emission computed tomography (SPECT) compared with follow-up CAG in stent-implanted patients who remained asymptomatic during the follow-up period.

METHODS AND RESULTS

The study group of 103 patients underwent both SPECT and CAG at 4-9 months after stent implantation. Restenosis occurred in 20 (19%) of 106 vessel territories, and a reversible perfusion defect was found in 32 (30%) territories. Sensitivity, specificity, positive and negative predictive values, and accuracy of SPECT were 65%, 78%, 41%, 91%, and 76%, respectively. The accuracy was lower in territories with a prior myocardial infarction (71%), in the left circumflex artery (58%), and in cases with three-vessel disease (63%). The negative predictive value was high, but 7 false negative cases included 4 cases with prior myocardial infarction, and 2 cases with reversible defects in other vessel territories.

CONCLUSIONS

Stress SPECT imaging is a useful tool for following up patients with coronary stent implantation, and follow-up CAG could be omitted in patients with negative SPECT imaging, no prior myocardial infarction, one- or two-vessel disease, and sufficient stress loading.