Joan M. Lacomis

Characterization of left atrium and distal pulmonary vein morphology using multidimensional computed tomography

OBJECTIVESnThis study was designed to examine the dimensions and morphology of left atrial (LA) and distal pulmonary veins (PVs) using multidetector helical computed tomography (MDCT).nnnBACKGROUNDnDetailed knowledge of LA and PV anatomy will assist in the development of techniques for ablative intervention. Multidetector helical computed tomography is a method for multidimensional imaging of cardiac anatomy.nnnMETHODSnMultidetector helical computed tomography was used to image the LA and PVs in 70 subjects with and 47 subjects without atrial fibrillation (AF). Accuracy of the MDCT data was confirmed by correlation with echocardiography and endocardial electrogram recordings.nnnRESULTSnLeft atrial and PV dimensions were significantly larger in AF versus non-AF subjects, men versus women, and subjects with persistent versus paroxysmal AF. There were no differences between groups in morphologic detail.nnnCONCLUSIONSnMultidetector helical computed tomography images of the LA and PVs are accurate and provide detailed anatomic information. Significant differences in dimensions but not morphologic detail were apparent between groups.

RV-pulmonary arterial coupling predicts outcome in patients referred for pulmonary hypertension

Objective Prognosis in pulmonary hypertension (PH) is largely determined by RV function. However, uncertainty remains about what metrics of RV function might be most clinically relevant. The purpose of this study was to assess the clinical relevance of metrics of RV functional adaptation to increased afterload. Methods Patients referred for PH underwent right heart catheterisation and RV volumetric assessment within 48u2005h. A RV maximum pressure (Pmax) was calculated from the RV pressure curve. The adequacy of RV systolic functional adaptation to increased afterload was estimated either by a stroke volume (SV)/end-systolic volume (ESV) ratio, a Pmax/mean pulmonary artery pressure (mPAP) ratio, or by EF (RVEF). Diastolic function of the RV was estimated by a diastolic elastance coefficient β. Survival analysis was via Cox proportional HR, and Kaplan–Meier with the primary outcome of time to death or lung transplant. Results Patients (n=50; age 58±13 yrs) covered a range of mPAP (13–79u2005mmu2005Hg) with an average RVEF of 39±17% and ESV of 143±89u2005mL. Average estimates of the ratio of end-systolic ventricular to arterial elastance were 0.79±0.67 (SV/ESV) and 2.3±0.65 (Pmax/mPAP-1). Transplantation-free survival was predicted by right atrial pressure, mPAP, pulmonary vascular resistance, β, SV, ESV, SV/ESV and RVEF, but after controlling for right atrial pressure, mPAP, and SV, SV/ESV was the only independent predictor. Conclusions The adequacy of RV functional adaptation to afterload predicts survival in patients referred for PH. Whether this can simply be evaluated using RV volumetric imaging will require additional confirmation.

The clinical epidemiology of pulmonary cryptococcosis in non-aids patients at a tertiary care medical center

Cryptococcus neoformans is a ubiquitous saprophytic fungus with worldwide distribution. It has been found in nature, primarily in association with bird droppings, but nonavian sources have been described as well (10). Although the lungs are thought to be the portal of entry for cryptococcus, pulmonary infection is uncommon. The organism is trophic to the central nervous system and the vast majority of recognized infections involve meningitis. Before the acquired immunodeficiency syndrome (AIDS) epidemic (1980), cryptococcosis was a rare infection, and pulmonary disease was described in 10%–45% of patients with cryptococcal meningitis (2). However, the true incidence of pulmonary cryptococcosis (PC) was not known, but was much lower than meningitis. Most PC cases were identified histologically and often at autopsy, with only about 20% diagnosed by culture (2, 3, 13). In recent years, many of the reports of cryptococcal infection have been in the human immunodeficiency virus (HIV)-positive population, and little is known of the disease in non-AIDS patients, particularly pulmonary involvement. At our institution, a tertiary care medical center with a large transplant program, sporadic cases of PC have occurred in solidorgan transplant recipients as well as in patients with a variety of different medical conditions. The purpose of our study was to investigate the epidemiology of PC in non-AIDS patients, and to determine predictors of outcome among these patients.

Myocardial bridging: noninvasive diagnosis with multidetector CT.

An epicardial segment of a coronary artery that courses through the myocardium is termed “myocardial bridging”. Generally, this is a benign condition but it may lead to angina, ischemia or infarction. The current diagnostic standard of reference is coronary catheter angiography. Intravascular ultrasound (IVUS) and intracoronary Doppler (ICD) have been recently introduced as well. These are all invasive imaging modalities. We describe the utilization of gated multidetector CT (MDCT) as a non-invasive alternative for diagnosis of this anomaly. Information regarding the tunneled coronary artery including its length, depth, precise location and surrounding myocardium is easily obtainable.

CT of the Pulmonary Veins

Atrial fibrillation (AF) is a common cardiac rhythm disturbance and its incidence is increasing. Radiofrequency catheter ablation (RFCA) is a highly successful therapy for treating AF, and its use is becoming more widespread; however, with its increasing use and evolving technique, known complications are better understood and new complications are emerging. Computed tomography (CT) of the pulmonary veins, or more correctly, the posterior left atrium (LA), has an established role in precisely defining the complex anatomy of the LA and pulmonary veins preablation and has an expanding role in identifying the myriad of possible complications postablation. The purposes of this article are: to review AF and RFCA; to discuss CT evaluation of the LA and pulmonary veins preablation; and to review the complications of RFCA focusing on the role of CT postablation.

The radiology of pulmonary cryptococcosis in a tertiary medical center.

Pulmonary cryptococcal infections occur in both immunocompetent and immunocompromised individuals, with a reported increased incidence of diffuse pulmonary disease in acquired immune deficiency syndrome (AIDS) patients. The authors observed no differences in the radiographic appearances of pulmonary cryptococcal disease between human immunodeficiency virus (HIV) patients and other immunocompromised individuals. Chest computed tomography (CT) contributes to a more comprehensive understanding of pulmonary cryptococcal infections.

Phenotyping the Right Ventricle in Patients with Pulmonary Hypertension

Right ventricular (RV) failure is associated with poor outcomes in pulmonary hypertension (PH). We sought to phenotype the RV in PH patients with compensated and decompensated RV function by quantifying regional and global RV structural and functional changes. Twenty‐two patients (age 51 ± 11, 14 females, mean pulmonary artery (PA) pressure range 13–79 mmHg) underwent right heart catheterization, echocardiography, and ECG‐gated multislice computed tomography of the chest. Patients were divided into three groups: Normal, PH with hemodynamically compensated, and decompensated RV function (PH‐C and PH‐D, respectively). RV wall thickness (WT) was measured at end‐diastole (ED) and end‐systole (ES) in three regions: infundibulum, lateral free wall, and inferior free wall. Globally, RV volumes progressively increased from Normal to PH‐C to PH‐D and RV ejection fraction decreased. Regionally, WT increased and fractional wall thickening (FWT) decreased in a spatially heterogeneous manner. Infundibular wall stress was elevated and FWT was lower regardless of the status of global RV function. In PH, there are significant phenotypic abnormalities in the RV even in the absence of overt hemodynamic RV decompensation. Regional changes in RV structure and function may be early markers of patients at risk for developing RV failure.

Free-Breathing, Motion-Corrected Late Gadolinium Enhancement Is Robust and Extends Risk Stratification to Vulnerable Patients

Background— Routine clinical use of novel free-breathing, motion-corrected, averaged late-gadolinium-enhancement (moco-LGE) cardiovascular MR may have advantages over conventional breath-held LGE (bh-LGE), especially in vulnerable patients. Methods and Results— In 390 consecutive patients, we collected bh-LGE and moco-LGE with identical image matrix parameters. In 41 patients, bh-LGE was abandoned because of image quality issues, including 10 with myocardial infarction. When both were acquired, myocardial infarction detection was similar (McNemar test, P=0.4) with high agreement (&kgr;=0.95). With artifact-free bh-LGE images, pixelwise myocardial infarction measures correlated highly (R 2=0.96) without bias. Moco-LGE was faster, and image quality and diagnostic confidence were higher on blinded review (P<0.001 for all). During a median of 1.2 years, 20 heart failure hospitalizations and 18 deaths occurred. For bh-LGE, but not moco-LGE, inferior image quality and bh-LGE nonacquisition were linked to patient vulnerability confirmed by adverse outcomes (log-rank P<0.001). Moco-LGE significantly stratified risk in the full cohort (log-rank P<0.001), but bh-LGE did not (log-rank P=0.056) because a significant number of vulnerable patients did not receive bh-LGE (because of arrhythmia or inability to hold breath). Conclusions— Myocardial infarction detection and quantification are similar between moco-LGE and bh-LGE when bh-LGE can be acquired well, but bh-LGE quality deteriorates with patient vulnerability. Acquisition time, image quality, diagnostic confidence, and the number of successfully scanned patients are superior with moco-LGE, which extends LGE-based risk stratification to include patients with vulnerability confirmed by outcomes. Moco-LGE may be suitable for routine clinical use.

The aortic root: Comparison of measurements from ECG-gated CT angiography with transthoracic echocardiography

Purpose The purpose of this study was to compare the measurements of the aortic root obtained from electrocardiographically (ECG)-gated computed tomography (CT) angiography (CTA) to the measurements obtained from transthoracic echocardiography (TTE). Materials and Methods This was a retrospective study in a patient population scanned at our institution between December 2005 and January 2007 with retrospectively ECG-gated CTA. ECG-gated CTA was performed with a 64-section helical CT scanner (Light speed, VCT, GE, Milwaukee, WI). Sixty-eight patients; 51 men and 17 women were included in this study. Aortic root diameters were measured by using double oblique reconstruction from axial source images. The TTE measurements of the aortic root were obtained from the reports that were performed within 2 months of CTA. Results The average aortic root diameter measured by TTE was 33±4.1u2009mm; on CTA it was 36.9±3.8u2009mm. The median difference between the 2 measurements was 3.9u2009mm which was significant (P<0.0001). In patients whose aortic root measurements with CTA were normal, the TTE measurements were also normal. However, in the group of patients with dilated aortic roots by CTA, TTE measurements were significantly lower and many were normal. In the group of patients with dilated aortic root by TTE, the CTA measurements of the aortic root were similarly increased. Conclusions Retrospective comparison of TTE and CTA measurements of the aortic root reveal that TTE measurements are substantially lower or even normal in patients found to have dilated aortic root by CTA.

Aggressive Aortic Arch and Carotid Replacement Strategy for Type A Aortic Dissection Improves Neurologic Outcomes

BACKGROUNDnInternational registries for acute type A aortic dissection (TAAD) demonstrate stagnant operative mortality rates in excess of 20% and stroke rates of 9% to 25%, with little global emphasis on stroke reduction or carotid involvement. Cerebral malperfusion with TAAD has been linked to poorer outcome. We hypothesize that concomitant carotid dissection or complex dissection flaps in the arch play a major role in stroke development and that aggressive reconstruction of the arch and carotid arteries can improve neurologic outcomes in TAAD.nnnMETHODSnA standardized protocol focused on expedient care, neurocerebral protection, and common carotid and total arch reconstruction was developed for 264xa0consecutive TAADs. Arch and complete carotid replacement was based on arch dissection anatomy, carotid involvement, or an intraarch tear. Neurocerebral monitoring with continuous electroencephalogram/somatosensory evoked potentials was used in all cases.nnnRESULTSnThe postoperative stroke and hospital mortality rates were 3.4% and 9.1%, and stroke rates by extent of arch replacement were 4%, 3%, and 0% for hemiarch, total arch, and total arch with complete carotid replacement, respectively. An intraoperative change in the electroencephalogram/somatosensory evoked potentials was strongly predictive of stroke and had a negative predictive value of 98.2%.nnnCONCLUSIONSnAn algorithmic approach to TAAD including (1) rapid transport-to-incision-to-cardiopulmonary bypass established centrally, (2) neurocerebral monitoring, (3) liberal use of total arch replacement for clearly defined indications (and hemiarch for all others), and (4) common carotid arterial replacement for concomitant carotid dissections significantly improves outcomes.