|M.Sc Student||Nakhleh Morad|
|Subject||Clinical Implications of Sleep Disordered Breathing in|
Patients Admitted for Acute Myocardial Infarction
|Department||Department of Medicine||Supervisors||Professor Doron Aronson|
|Dr. Lena Lavie|
|Full Thesis text|
Background: Sleep disordered breathing (SDB) is highly prevalent in the adult population. There is growing awareness that SDB is associated with an increased risk for cardiovascular events, including acute myocardial infarction (AMI) and stroke. Several mechanisms provide a link between SDB and atherosclerosis including systemic Inflammation, endothelial dysfunction, oxidative stress, increased platelet activity and sympathetic over activity.
However, few data are available on the prevalence, metabolic and clinical consequences of SDB in patients with AMI.
The objective of the present study is to assess the impact of SDB on metabolic and left ventrical functional alterations and clinical outcomes after AMI.
Methods and Design: The study population included patients hospitalized with AMI and survived the first 5 days. All patients underwent a full night sleep study using the Watch Pat-100. SDB was defined as an apnea hypopnea index(AHI)≥20 events/hour. In the morning following the sleep study, venous blood samples were obtained for C-reactive protein(CRP) and markers of oxidative stress(Thiobarbituric Reactive Substances[TBARS], lipid peroxides[PD] and serum paraoxonase-1[PON-1] arylesterase activity). Echocardiography was performed to evaluate of cardiac dimensions, left ventricular functions and pulmonary artery systolic pressure.
Following hospital discharge, clinical endpoint information was acquired by reviewing the national death registry and hospital medical file, and by contacting each patient individually and independently.
Results: 180 patients with AMI were enrolled to the study. 79 patients (44%) were diagnosed with SDB. Those Patients were older and had higher BMI. CRP levels were higher among SDB patients (9.5 Vs. 16.5 mg/L, P=0.049).CRP levels increased with increasing severity of SDB(Median CRP levels 9.5,15.9 and 25.9mg/L in patients with AHI<20,20-40 and >40events/h respectively;P=0.01). TBARS were lower among the SDB group (14 Vs. 11.5 nmol MDA/mL P=0.006), while PD and PON-1 were similar. Echocardiography revealed larger left arterial dimension (3.8 ±0.5 vs. 4.2±0.4cm,P<0.0001), and higher pulmonary artery systolic pressure (30±8 vs. 37±7 mmHg,p<0.0001) among AMI patients with SDB. There was a moderate positive correlation between PASP and AHI (r=0.40,P=0.0002). After a mean follow up of 28 months, no significant differences were observed between the study groups with regard to clinical outcomes, including death, heart failure, myocardial infarction and unstable angina.
Conclusion: In conclusion, we found a high prevalence of previously undiagnosed SDB among patients admitted to hospital with AMI. SDB in the setting of AMI is associated with higher hs-CRP levels and with higher pulmonary artery systolic pressure. However, SDB after AMI was not associated with adverse clinical outcomes.