Posttraumatic Stress Disorder, Myocardial Perfusion, and Myocardial Blood Flow: A Longitudinal Twin Study

Abstract

Background: The link between posttraumatic stress disorder (PTSD) and ischemic heart disease remains elusive owing to a shortage of longitudinal studies with a clinical diagnosis of PTSD and objective measures of cardiac compromise.

Methods: We performed positron emission tomography in 275 twins who participated in two examinations approximately 12 years apart. At both visits, we obtained a clinical diagnosis of PTSD, which was classified as long-standing (both visit 1 and visit 2), late onset (only visit 2), and no PTSD (no PTSD at both visits). With positron emission tomography, we assessed myocardial flow reserve (MFR), which, in absence of significant coronary stenoses, indexes coronary microvascular function. We compared positron emission tomography data at visit 2 across the three categories of longitudinally assessed PTSD and examined changes between the two visits.

Results: Overall, 80% of the twins had no or minimal obstructive coronary disease. Yet, MFR was depressed in twins with PTSD and was progressively lower across groups with no PTSD (2.13), late-onset PTSD (1.97), and long-standing PTSD (1.93) (p = .01). A low MFR (a ratio <2.0) was present in 40% of the twins without PTSD, in 56% of those with late-onset PTSD, and in 72% of those with long-standing PTSD (p < .001). Associations persisted in multivariable analysis, when examining changes in MFR between visit 1 and visit 2, and within twin pairs. Results were similar by zygosity.

Conclusions: Longitudinally, PTSD is associated with reduced coronary microcirculatory function and greater deterioration over time. The association is especially noted among twins with chronic, long-standing PTSD and is not confounded by shared environmental or genetic factors.

Keywords: Cardiovascular disease; Epidemiology; Myocardial ischemia; Positron emission tomography; Posttraumatic stress disorder; Twins.

Figure 1.

Participant flow diagram and construction of the analytical sample. The baseline assessment (Visit 1) included 283 twin pairs without a history of cardiovascular disease based on Registry surveys. Visit 1 was completed between 2002 and 2010 and included myocardial perfusion imaging with positron emission tomography (PET). From this sample we invited 504 twins who were still alive (252 pairs) to participate in a follow-up evaluation, which was completed in person or over the phone (for those who were not able to travel) on average 12 years after Visit 1. A total of 393 twins participated in the follow-up study (78%), and among them, 279 twins (including 124 pairs and 31 single twins) completed the in-person visit, when cardiac imaging with PET was repeated (Visit 2). Of the 279 participants in the in-person Visit 2, 275 twins (122 twin pairs and 31 single twins) had complete PET imaging data and represent our main analytical sample. Of these, 240 twins had both Visit 1 and Visit 2 perfusion data and 207 twins (95 pairs and 17 single) had quantitative PET data of MBF at both visits. * Two twin pairs were added to the database after the original publication based on 281 twin pairs. † Of the 72 twins who died either prior to recruitment or during recruitment, 17 died of cardiovascular disease, 21 died of cancer, and the rest died of miscellaneous other causes or the cause of death was unknown.

Figure 2.

Association between myocardial flow reserve and PTSD status assessed longitudinally taking into account current PTSD status at each time point. Never PTSD: no lifetime or current PTSD at Visit 1 and no current PTSD at Visit 2. Remitted PTSD: lifetime or current PTSD at Visit 1 and no current PTSD at Visit 2. Current, Not Chronic PTSD: no current PTSD at Visit 1 but current PTSD at Visit 2. Current, Chronic PTSD: current PTSD at both Visit 1 and Visit 2. Top Panel: Mean (± standard error) myocardial flow reserve at visit 2. Bottom Panel: Mean (± standard error) change in myocardial flow reserve between Visit 1 and Visit 2, expressed as number of standard deviations (a negative value indicated a decline in MFR). All data adjusted for age, current and past smoking, BMI, physical activity (Baecke score), history of hypertension, history of coronary disease, and statin use. All models for the analysis of change in MFR also adjusted for Visit 1 MFR. Abbreviations: PTSD: posttraumatic stress disorder; MFR: myocardial flow reserve. * p<0.05 compared with No PTSD