Amgad N. Makaryus

Planning and Guidance of Cardiac Resynchronization Therapy–Lead Implantation by Evaluating Coronary Venous Anatomy Assessed with Multidetector Computed Tomography

Objectives We sought to evaluate the utility of multidetector computed tomography (MDCT) in preoperative planning of cardiac resynchronization therapy (CRT) device implantation. Background Variation in coronary venous anatomy can affect optimal lead placement and may warrant preimplantation visualization prior to CRT lead placement. Methods Prospective randomized enrollment of 29 patients (17 males; mean age at implant 66.7 ± 12.8 years) was undertaken. Patients were randomized to preimplantation MDCT (GE® 64-detector Lightspeed, n = 16) or no MDCT. Implantation was planned based on three-dimensional coronary venous reconstruction as visualized in the CT group. Measurement of coronary sinus (CS) angulation, CS ostial (os) diameter, right atrial (RA) width, volume, and height was undertaken prior to implant. Intraoperative CS lead implantation times (introduction, cannulation, and left ventricular [LV] lead positioning), procedure time, fluoroscopy time, and venogram contrast volume were measured to determine if there was a difference between patients who underwent preimplant CT scan and those who did not. Results CS os diameter (mean = 13.8 ± 2.9 cm) was inversely correlated with total fluoroscopy time (r = -0.57, P = .008), and total procedure time, but this correlation was not statistically significant (r = - 0.36, P = 0.12). RA width (mean = 52.8 ± 9.9 cm) was associated with a shorter total procedure time (r = −0.44, P = .047) and LV lead positioning time (r = −0.33, P = .012). There were no statistically significant differences between the CT group and the non-CT group with respect to total intraoperative and fluoroscopy times or venogram contrast volumes. Total procedure time was longer in the CT group but the difference was not statistically significant (94 ± 27.2 vs. 74.7 ± 26.6; P = .065). Conclusion Noninvasive visualization of the coronary venous anatomy before CRT implantation can be used as a guide for lead placement. While no significant differences were noted between the two groups with respect to intraoperative variables, CS os diameter and RA width inversely correlated to a shorter procedure time and LV lead positioning time, respectively. Further clinical trials regarding the utility of MDCT to visualize coronary venous anatomy prior to CRT implantation for procedural planning and lead placement guidance are warranted.

Implications of Gender Difference in Coronary Calcification as Assessed by CT Coronary Angiography

Background Arterial calcium as measured by 64-slice computed tomography coronary angiography (64-CT) is a reliable predictor of cardiovascular disease risk. Lipid-rich plaques with lower degrees of calcification may pose greater risk for adverse coronary events than more stabilized calcified plaques as a result of the increased risk of plaque rupture, migration, and subsequent acute coronary syndrome. We sought to examine coronary artery calcium scores as measured via 64-CT to assess the extent of calcification and plaque distribution in women compared to men. Methods A total of 138 patients referred for 64-CT were evaluated. Computerized tomographic angiography was performed using the GE LightSpeed VCT. Subgroup analysis comparing male and female data (including demographic data) was performed. All major coronary arteries were analyzed for coronary stenosis/plaque characterization as well as total vessel calcium (Agatston) score quantification. Patient demographics and coronary risk factors were recorded. Results A total of 552 coronary arteries were evaluated in 138 patients (85 men, 53 women). The average age for females was 64.4 ± 10.8 years and for males 60.0 ± 12.8 years. The only demographic/cardiovascular risk factor in which the difference between men and women was significant was smoking history, where 23.5% of men had a history of smoking while only 9.6% of females endorsed having a smoking history (P < 0.044). On comparison of all total vessel calcium scores, males had a higher total mean calcium score than females in each individual vessel. The results were as follows for males versus females, respectively: left main total vessel calcium score 46.49 versus 16.71 (P = 0.167); left anterior descending 265.21 versus 109.6 (P < 0.003); left circumflex 130.5 versus 39.7 (P < 0.004); and right coronary 213.5 versus 73.8 (P < 0.01). The odds of having a total calcium score >100 (versus not) was 3.62 times greater in males relative to females, given that all the other cardiovascular risk factors are adjusted for (95% confidence interval: 1.37-9.54). On average, men had an average of 2.1 ± 1.5 epicardial vessels with a calcium score ≥11 compared to 1.3 ± 1.4 for women (P < 0.005). Conclusion There are clear differences between males and females regarding total vessel calcium scores and therefore risk of future adverse coronary events. Males tended to have higher average calcium scores in each coronary artery than females with a greater tendency to have multiple vessel involvement. Using this information, more large-scale, randomized controlled studies should be performed to correlate differences in the extent of coronary calcification with the observed variance in clinical presentation during coronary events between males and females as a means to potentially establish gender-specific therapeutic regimens.

Multi-Detector Coronary CT Imaging for the Identification of Coronary Artery Stenoses in a “Real-World” Population

Background Multi-detector computed tomography (CT) has emerged as a modality for the non-invasive assessment of coronary artery disease (CAD). Prior studies have selected patients for evaluation and have excluded many of the “real-world” patients commonly encountered in daily practice. We compared 64-detector-CT (64-CT) to conventional coronary angiography (CA) to investigate the accuracy of 64-CT in determining significant coronary stenoses in a “real-world” clinical population. Methods A total of 1,818 consecutive patients referred for 64-CT were evaluated. CT angiography was performed using the GE LightSpeed VCT (GE® Healthcare). Forty-one patients in whom 64-CT results prompted CA investigation were further evaluated, and results of the two diagnostic modalities were compared. Results A total of 164 coronary arteries and 410 coronary segments were evaluated in 41 patients (30 men, 11 women, age 39-85 years) who were identified by 64-CT to have significant coronary stenoses and who thereafter underwent CA. The overall per-vessel sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at the 50% stenosis level were 86%, 84%, 65%, 95%, and 85%, respectively, and 77%, 93%, 61%, 97%, and 91%, respectively, in the per-segment analysis at the 50% stenosis level. Conclusion 64-CT is an accurate imaging tool that allows a non-invasive assessment of significant CAD with a high diagnostic accuracy in a “real-world” population of patients. The sensitivity and specificity that we noted are not as high as those in prior reports, but we evaluated a population of patients that is typically encountered in clinical practice and therefore see more “real-world” results.

Nearly Asymptomatic Eight-Month Thoracic Aortic Dissection

Thoracic aortic dissection is a rare, but lethal, medical condition that is either misdiagnosed as a myocardial infarction or overlooked completely. Though thoracic aortic dissections are commonly diagnosed in patients exhibiting sharp chest pain, there are some notable cases where patients do not report the expected severity of pain. We report a unique case of a patient with a thoracic aortic dissection who was initially nearly asymptomatic for eight months, in order to heighten awareness, highlight diagnosis protocol, and improve prognosis for this commonly misdiagnosed, but fatal, condition.

Diabetes and Coronary Artery Disease – Pathophysiologic Insights and Therapeutic Implications

Cardiovascular disease is the leading cause of morbidity and mortality among peo‐ ple with diabetes worldwide, accounting for 60% of all deaths in diabetics. Despite advances in our pathophysiologic understanding of diabetic co-morbidities and measures to help counter these, diabetics still remain at increased risk for cardiovas‐ cular disease complicating our overall approach to management. Diabetics, in par‐ ticularly type 2, are often fraught with additional risk factors contributing to their overall propensity for developing cardiovascular disease. These include, but are not limited to, obesity, dyslipidemia, poor glycemic control, lack of physical activity, and hypertension. In response to this, research driven guidelines focusing on pri‐ mary prevention have continued to arise with new clinical targets and goals sub‐ stantially changing our approach with the diabetic population. It is important to note early on, type 1 diabetics carry a higher risk of cardiovascular disease for which the pathophysiology is only recently being elucidated. The underlying rela‐ tionship between cardiovascular events and risk factors is, however, not well un‐ derstood. For this reason, management approaches to risk reduction have been extrapolated from experience in type 2 diabetes mellitus. The purpose of this chap‐ ter is to present the conclusions of current literature pertaining to blood pressure and blood glucose control, cholesterol management, aspirin therapy, and lifestyle modification. We present a synthesis of the new guidelines, and clinical targets, in‐ cluding preventative measures for subclinical cardiovascular disease for the con‐ temporary management of patients with diabetes mellitus.

Introductory Editorial — Cardiovascular Imaging: Current Developments in Research and Clinical Practice

This supplement aims to provide readers with a comprehensive overview of current developments in this important area. Topics addressed span non-invasive and invasive cardiovascular imaging and include but are not limited to advances in applied (translational) research in: Echocardiography § § Cardiac computer tomography § § Cardiac MRI and spectroscopy § § Magnetic resonance angiography § § Cardiac positron emission tomography § §