Value of cardiac CT in comprehensive aortic valve and root evaluation before percutaneous aortic valve replacement.

BACKGROUND: Aortic stenosis (AS) is the most frequent valvular heart disease, and patients who develop AS are at a high risk of sudden death. There is no medical cure available, and aortic valve replacement is the only effective treatment for advanced disease. Preoperative evaluation is the cornerstone of therapy and is necessary for selecting the implantation technique and valve. PURPOSE: To evaluate the role of cardiac CT in comprehensive aortic valve and aortic root evaluation before percutaneous aortic valve replacement. MATERIAL AND METHODS: Thirty-four patients with severe aortic valve stenosis were evaluated by cardiac CT. The aortic valve calcification grade defined by cardiac CT was compared to the operative findings. The mean calculated aortic annulus diameter (CAAD) measured by cardiac CT was compared to the aortic annulus diameter measured by transthoracic echocardiography (TTE) as well as during the operation. The distances from the aortic valve annulus to the coronary ostia (right and left) were measured by cardiac CT and compared to the intraoperative measurements. The findings from the CT coronary angiography and conventional coronary angiography were compared. RESULTS: There was strong agreement (k = 0.865) between the calcification grade by cardiac CT and the intraoperative grading. There was a stronger correlation (r = 0.948) between the CAAD assessed by cardiac CT and intraoperatively compared to the correlation between the intraoperative versus TTE measurements (r = 0.660). The distances measured between the aortic annulus and the right and left coronary artery ostia by cardiac CT were strongly correlated with the distances measured intraoperatively (r = 0.966 and 0.940 in the right and left sides, respectively). Cardiac CT detected three coronary artery stenotic lesions and three patent stents. All findings were confirmed by conventional coronary angiography. Thirteen percent of the evaluated coronary artery segments were of non-diagnostic quality by cardiac CT. CONCLUSION: Cardiac CT substantially facilitates the assessment of aortic root morphology prior to aortic valve replacement.

Prevention of preterm birth: a randomized trial of vaginal compared with intramuscular progesterone.

OBJECTIVE: To assess efficacy and tolerability of vaginal compared with intramuscular progesterone in reducing the rate of recurrent preterm birth before 34 weeks of gestation. DESIGN: Prospective randomized study. SETTING: Obstetrics and Gynecology Department, Armed Forces Hospital Southern Region, Kingdom of Saudi Arabia. SAMPLE: Five-hundred and eighteen women with a prior history of preterm birth. METHODS: Women were randomized to receive either 90 mg of vaginal progesterone gel once daily or 250 mg of intramuscular progesterone weekly. Treatment began between 14 and 18 weeks of gestation and continued until 36 complete weeks of gestation, delivery or the occurrence of premature rupture of membranes. MAIN OUTCOME MEASURES: The primary outcome measure was delivery before 34 weeks of gestation. The secondary outcome measures were PTB between 34 and 37 weeks of gestation and neonatal outcomes including birthweight, neonatal death, and the need for admission to the neonatal intensive care unit. RESULTS: The baseline characteristics of the study participants were similar. Two-hundred and thirty-eight (94.1%) patients in the vaginal group and 226 (90.8%) patients in the intramuscular group were compliant with their medications. Vaginal progesterone was associated with a lower percentage of deliveries before 34 weeks of gestation than the intramuscular preparation (p= 0.02). This association was also observed at 28 and 32 weeks of gestation (p= 0.04). Adverse effects were reported in 14.1% of patients in the intramuscular group, but in only 7.5% of patients in the vaginal group (p= 0.017). CONCLUSIONS: Vaginal progesterone was more effective than intramuscular progesterone for the prevention of preterm birth and had fewer adverse effects.

Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve.

BACKGROUND: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. PURPOSE: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. MATERIAL AND METHODS: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. RESULTS: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 ± 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. CONCLUSION: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation.

Low-radiation-dose dual-phase MDCT protocol with split contrast media dose and time optimization: protocol design for renal donors evaluation.

BACKGROUND: A routine, multiphase, computed tomography (CT) protocol is associated with high radiation exposure to potential kidney donors. To reduce radiation exposure, several authors have suggested a reduction in the number of phases. PURPOSE: To evaluate a low-radiation-dose, dual-phase protocol (i.e. a protocol with an unenhanced phase and combined vascular and excretory phase) for the preoperative evaluation of potential renal donors. MATERIAL AND METHODS: Sixty-five potential renal donors were divided into two groups. The first group was scanned with a routine quadric-phase protocol (non-contrast, arterial, venous, and delayed), and the second group was scanned with a triple-phase protocol (dual phase protocol + venous phase). In the second group, we replaced CT angiography with a routine abdominal CT technique. In addition to the evaluation of renal arteries, veins, and excretory systems, the radiation dose of the suggested protocol was compared to that of the routine quadric-phase protocol. RESULTS: The suggested protocol was efficient in the evaluation of renal arteries, veins, and excretory systems in all studied potential renal donors. Renal arteries were well visualized in the combined vascular excretory phase using the routine abdominal CT technique; no significant difference was noted when these results were compared to those obtained from the CT angiography used in the quadric-phase protocol. The mean effective radiation dose of our suggested dual-phase protocol was only 34% of the dose resulting from the routine quadric-phase protocol. CONCLUSION: Use of a low-radiation, dual-phase, CT protocol, which relied on both an unenhanced phase and a combined vascular and excretory phase, significantly reduced radiation dose. Furthermore, the proposed protocol provides adequate visualization of renal arteries and veins, and affords sufficient opacification of the urinary tract using improved acquisition triggering.

Prediction of pulmonary embolism outcome and severity by computed tomography.

BACKGROUND: Pulmonary embolism (PE) is the third most common cause of cardiovascular death. When PE is fatal, right ventricular failure usually occurs within the first few hours, so right ventricular dysfunction (RVD) should be diagnosed rapidly to identify patients who could benefit from fibrinolytic therapy. PURPOSE: To determine whether quantification of PE with computed tomography (CT) pulmonary angiography and ventricular measurements is of value in the diagnosis of PE severity and prediction of patient outcome. MATERIAL AND METHODS: Multidetector-row CT studies of 48 hospitalized patients with proven pulmonary embolism were reviewed. Pulmonary artery (PA) obstructive index was derived for each patient on the basis of location and degree of obstruction. Ventricular measurements, including right ventricular (RV) short axis, left ventricular (LV) short axis, and RV/LV ratio, were evaluated and compared among survivors and nonsurvivors. Also, the ventricular measurements were correlated with the PA obstructive index. RV/LV ratio and related PA obstructive index were correlated to the patient outcome and hospital stay. RESULTS: Comparison of the PA obstructive index and ventricular measurements between survivors and nonsurvivors showed significant difference in PA obstructive index (P<0.001), RV short axis (P<0.001), and RV/LV ratio (P=0.03), and no significant difference was noted in LV short axis (P=0.95). Good correlation was found between PA obstructive index and LV short axis (-0.326), RV short axis (0.539), and RV/LV ratio (0.696). A significant difference was found between the PA obstructive indexes of the different categories of RV/LV ratio (P<0.001). CONCLUSION: PA obstructive index of more than 50% and RV/LV ratio >1.5 are useful diagnostic criteria for severe PE and poor patient outcome.