Qualitative Evaluation of Common Quantitative Metrics for Clinical Acceptance of Automatic Segmentation: a Case Study on Heart Contouring from CT Images by Deep Learning Algorithms.

Organs-at-risk contouring is time consuming and labour intensive. Automation by deep learning algorithms would decrease the workload of radiotherapists and technicians considerably. However, the variety of metrics used for the evaluation of deep learning algorithms make the results of many papers difficult to interpret and compare. In this paper, a qualitative evaluation is done on five established metrics to assess whether their values correlate with clinical usability. A total of 377 CT volumes with heart delineations were randomly selected for training and evaluation. A deep learning algorithm was used to predict the contours of the heart. A total of 101 CT slices from the validation set with the predicted contours were shown to three experienced radiologists. They examined each slice independently whether they would accept or adjust the prediction and if there were (small) mistakes. For each slice, the scores of this qualitative evaluation were then compared with the Sørensen-Dice coefficient (DC), the Hausdorff distance (HD), pixel-wise accuracy, sensitivity and precision. The statistical analysis of the qualitative evaluation and metrics showed a significant correlation. Of the slices with a DC over 0.96 (N = 20) or a 95% HD under 5 voxels (N = 25), no slices were rejected by the readers. Contours with lower DC or higher HD were seen in both rejected and accepted contours. Qualitative evaluation shows that it is difficult to use common quantification metrics as indicator for use in clinic. We might need to change the reporting of quantitative metrics to better reflect clinical acceptance.

Rationale and design of the PHOspholamban RElated CArdiomyopathy intervention STudy (i-PHORECAST).

BACKGROUND: The p.Arg14del (c.40_42delAGA) phospholamban (PLN) pathogenic variant is a founder mutation that causes dilated cardiomyopathy (DCM) and arrhythmogenic cardiomyopathy (ACM). Carriers are at increased risk of malignant ventricular arrhythmias and heart failure, which has been ascribed to cardiac fibrosis. Importantly, cardiac fibrosis appears to be an early feature of the disease, occurring in many presymptomatic carriers before the onset of overt disease. As with most monogenic cardiomyopathies, no evidence-based treatment is available for presymptomatic carriers. AIMS: The PHOspholamban RElated CArdiomyopathy intervention STudy (iPHORECAST) is designed to demonstrate that pre-emptive treatment of presymptomatic PLN p.Arg14del carriers using eplerenone, a mineralocorticoid receptor antagonist with established antifibrotic effects, can reduce disease progression and postpone the onset of overt disease. METHODS: iPHORECAST has a multicentre, prospective, randomised, open-label, blinded endpoint (PROBE) design. Presymptomatic PLN p.Arg14del carriers are randomised to receive either 50 mg eplerenone once daily or no treatment. The primary endpoint of the study is a multiparametric assessment of disease progression including cardiac magnetic resonance parameters (left and right ventricular volumes, systolic function and fibrosis), electrocardiographic parameters (QRS voltage, ventricular ectopy), signs and/or symptoms related to DCM and ACM, and cardiovascular death. The follow-up duration is set at 3 years. BASELINE RESULTS: A total of 84 presymptomatic PLN p.Arg14del carriers (n = 42 per group) were included. By design, at baseline, all participants were in New York Heart Association (NHYA) class I and had a left ventricular ejection fraction > 45% and < 2500 ventricular premature contractions during 24-hour Holter monitoring. There were no statistically significant differences between the two groups in any of the baseline characteristics. The study is currently well underway, with the last participants expected to finish in 2021. CONCLUSION: iPHORECAST is a multicentre, prospective randomised controlled trial designed to address whether pre-emptive treatment of PLN p.Arg14del carriers with eplerenone can prevent or delay the onset of cardiomyopathy. iPHORECAST has been registered in the clinicaltrials.gov-register (number: NCT01857856).

Calcification as a risk factor for rupture of abdominal aortic aneurysm.

OBJECTIVES: Abdominal aortic aneurysm (AAA) is a major cause of death in developed countries. The AAA diameter is still the only validated prognostic measure for rupture, and therapeutic interventions are initiated accordingly. This still leads to unnecessary interventions in some cases or unidentified impending ruptures. Vascular calcification has been validated abundantly as a risk factor in the cardiovascular field and may strengthen the rupture risk assessment of the AAA. With this study we aim to assess the correlation between AAA calcification and rupture risk in a retrospective unmatched case-control population. METHODS: A database of 334 AAA patients was evaluated. Three groups were formed: elective (eAAA; n = 233), ruptured (rAAA; n = 73) and symptomatic non-ruptured (sAAA; n = 28) AAA patients. The Abdominal Aortic Calcification-8 score (AAC-8) was used to measure the severity of vascular calcification. RESULTS: The AAA diameter (61 ± 12 mm vs. 74 ± 21 mm; p < .001) and AAC-8 score (3.4 ± 2 points vs. 4.9 ± 2.3 points; p < .001) of the eAAA and the combined rAAA and sAAA groups, respectively, were significantly different after univariate analysis. Multivariate analysis showed that larger AAA diameter (odds ratio [OR]: 1.048/mm increase; 95% confidence interval [CI]: 1.042-1.082; p < .001) and a higher AAC-8 score (OR: 1.34/point increase; 95% CI: 1.19-1.53; p < .001) were significantly associated with development into a sAAA or rAAA. Peripheral artery disease was significantly correlated to eventual elective treatment (OR: 0.39; 95% CI: .15-1; p = .049). CONCLUSION: This study suggests a trend of an increased degree of calcification in symptomatic or even ruptured AAA patients compared with elective AAA patients.

Myocardial perfusion reserve and contractile pattern after beta-blocker therapy in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: In Idiopathic Dilated Cardiomyopathy (IDC) an imbalance between myocardial oxygen consumption and supply has been postulated. The ensuing subclinical myocardial ischemia may contribute to progressive deterioration of LV function. beta-blocker is the therapy of choice in these patients. However, not all patients respond to the same extent. The aim of this study was to elucidate whether differences between responders and non-responders can be identified with respect to regional myocardial perfusion reserve (MPR) and contractile performance. METHODS: Patients with newly diagnosed IDC underwent Positron Emission Tomography (PET) scanning using both (13)N-ammonia as a perfusion tracer (baseline and dipyridamole stress), and (18)F-fluoro-deoxyglucose as a metabolism tracer, and a dobutamine stress MRI. MRI and PET were repeated 6 months after maximal beta-blocker therapy. MPR (assessed by PET) as well as wall motion score (WMS, assessed by MRI) were evaluated in a 17 segment-model. Functional response to beta-blocker therapy was assigned as a stable or improved LVEF or diminished LVEF. RESULTS: Sixteen patients were included (age 47.9 +/- 11.5 years; 12 males, LVEF 28.6 +/- 8.4%). Seven patients showed improved LVEF (9.7 +/- 3.1%), and nine patients did not show improved LVEF (-3.4 +/- 3.9%). MPR improved significantly in responders (1.56 +/- .23 to 1.93 +/- .49, P = .049), and MPR decreased in non-responders; however, not significantly (1.98 +/- .70 to 1.61 +/- .28, P = .064), but was significantly different between both groups (P = .017) after beta-blocker therapy. A significant correlation was found between change in perfusion reserve and change in LVEF: a decrease in perfusion reserve was associated with a decrease in LVEF and vice versa. Summed rest score of wall motion in responders improved from 26 to 21 (P = .022) whereas in non-responders no change was observed from 26 to 25) (P = ns). Summed stress score of wall motion in responders improved from 23 to 21 (P = .027) whereas in non-responders no change was observed from 27 to 26) (P = ns). CONCLUSION: In IDC patients, global as well as regional improvement after initiation of beta-blocker treatment is accompanied by an improvement in regional perfusion parameters. On the other hand in IDC patients with further left ventricular function deterioration after initiation of beta-blocker therapy this is accompanied by a decrease in perfusion reserve.

Is there an indication for computed tomography and magnetic resonance imaging in the evaluation of coronary artery bypass grafts?

This meta-analysis evaluates the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for bypass graft occlusion and stenosis detection compared with coronary angiography in post-coronary artery bypass graft patients. The indication for noninvasive imaging in post-coronary artery bypass graft patients with these techniques is discussed. Overall, MRI had significantly lower sensitivity (81%) and specificity (91%) for occlusion detection than MDCT (96% and 98%, respectively). Only 2 studies assessed the accuracy of stenosis detection with MRI. Stenosis detection with MDCT had a pooled sensitivity of 89% and specificity of 97%. Multidetector computed tomography is therefore superior to MRI for the noninvasive detection of coronary bypass graft occlusion and stenosis. For stenosis detection, the accuracy of MDCT is, however, not sufficient to warrant a wide clinical use. The remaining indication for MRI-guided bypass graft assessment is in combination with myocardial evaluation such as magnetic resonance perfusion, wall motion, and stress test as a "one-stop-shop" procedure.

Right ventricular-vascular coupling ratio in pediatric pulmonary arterial hypertension: A comparison between cardiac magnetic resonance and right heart catheterization measurements.

BACKGROUND: In pulmonary arterial hypertension (PAH), right ventricular (RV) failure is the main cause of mortality. Non-invasive estimation of ventricular-vascular coupling ratio (VVCR), describing contractile response to afterload, could be a valuable tool for monitoring clinical course in children with PAH. This study aimed to test two hypotheses: VVCR by cardiac magnetic resonance (VVCRCMR) correlates with conventional VVCR by right heart catheterization (VVCRRHC) and both correlate with disease severity. METHODS AND RESULTS: Twenty-seven patients diagnosed with idiopathic and associated PAH without post-tricuspid shunt, who underwent RHC and CMR within 17 days at two specialized centers for pediatric PAH were retrospectively studied. Clinical functional status and hemodynamic data were collected. Median age at time of MRI was 14.3 years (IQR: 11.1-16.8), median PVRi 7.6 WU × m2 (IQR: 4.1-12.2), median mPAP 40 mm Hg (IQR: 28-55) and median WHO-FC 2 (IQR: 2-3). VVCRCMR, defined as stroke volume/end-systolic volume ratio was compared to VVCRRHC by single-beat pressure method using correlation and Bland-Altman plots. VVCRCMR and VVCRRHC showed a strong correlation (r = 0.83, p < 0.001). VVCRCMR and VVCRRHC both correlated with clinical measures of disease severity (pulmonary vascular resistance index [PVRi], mean pulmonary artery pressure [mPAP], mean right atrial pressure [mRAP], and World Health Organization functional class [WHO-FC]; all p ≤ 0.02). CONCLUSIONS: Non-invasively measured VVCRCMR is feasible in pediatric PAH and comparable to invasively assessed VVCRRHC. Both correlate with functional and hemodynamic measures of disease severity. The role of VVCR assessed by CMR and RHC in clinical decision-making and follow-up in pediatric PAH warrants further clinical investigation.

Visualization of anomalous coronary arteries on dual-source computed tomography.

The purpose of this study is to assess the capability of dual-source computed tomography (DSCT) in evaluating coronary artery anomalies. Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death. In 16 patients (12 men, mean age 50 +/- 14 years), anomalous coronary arteries were detected on contrast-enhanced DSCT in a patient cohort of 230 individuals (incidence of 7%). Six different types of anomalies were diagnosed (three fistula, four anomalies of the circumflex artery, four anomalous right coronary arteries, three anomalies of the left coronary artery, one absent left main coronary artery, and one left coronary artery arising from the pulmonary trunk). Of the 16 patients, 10 also underwent conventional coronary angiography (CAG). Retrospective evaluation of the CAGs by an experienced interventional cardiologist resulted in a precise diagnosis in 50% of patients. With DSCT, sufficient image quality and exact visualization of the aberrant anatomy were achieved in all patients. Therefore, DSCT seems to be an accurate diagnostic tool for examining the precise origin, course, and shape of aberrant coronary arteries.

Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems.

The objective of this study was to evaluate the influence of iterative reconstruction on coronary calcium scores (CCS) at different heart rates for four state-of-the-art CT systems. Within an anthropomorphic chest phantom, artificial coronary arteries were translated in a water-filled compartment. The arteries contained three different calcifications with low (38 mg), medium (80 mg) and high (157 mg) mass. Linear velocities were applied, corresponding to heart rates of 0, < 60, 60-75 and > 75 bpm. Data were acquired on four state-of-the-art CT systems (CT1-CT4) with routinely used CCS protocols. Filtered back projection (FBP) and three increasing levels of iterative reconstruction (L1-L3) were used for reconstruction. CCS were quantified as Agatston score and mass score. An iterative reconstruction susceptibility (IRS) index was used to assess susceptibility of Agatston score (IRSAS) and mass score (IRSMS) to iterative reconstruction. IRS values were compared between CT systems and between calcification masses. For each heart rate, differences in CCS of iterative reconstructed images were evaluated with CCS of FBP images as reference, and indicated as small (< 5%), medium (5-10%) or large (> 10%). Statistical analysis was performed with repeated measures ANOVA tests. While subtle differences were found for Agatston scores of low mass calcification, medium and high mass calcifications showed increased CCS up to 77% with increasing heart rates. IRSAS of CT1-T4 were 17, 41, 130 and 22% higher than IRSMS. Not only were IRS significantly different between all CT systems, but also between calcification masses. Up to a fourfold increase in IRS was found for the low mass calcification in comparison with the high mass calcification. With increasing iterative reconstruction strength, maximum decreases of 21 and 13% for Agatston and mass score were found. In total, 21 large differences between Agatston scores from FBP and iterative reconstruction were found, while only five large differences were found between FBP and iterative reconstruction mass scores. Iterative reconstruction results in reduced CCS. The effect of iterative reconstruction on CCS is more prominent with low-density calcifications, high heart rates and increasing iterative reconstruction strength.

Influence of heart rate on coronary calcium scores: a multi-manufacturer phantom study.

To evaluate the influence of heart rate on coronary calcium scores (CCS) using a dynamic phantom on four high-end computed tomography (CT) systems from different manufacturers. Artificial coronary arteries were moved in an anthropomorphic chest phantom at linear velocities, corresponding to < 60, 60-75 and > 75 beats per minute (bpm). Data was acquired with routinely used clinical protocols for CCS on four high-end CT systems (CT1-CT4). CCS, quantified as Agatston and mass scores were compared to reference scores at < 60 bpm. Influence of heart rate was assessed for each system with the cardiac motion susceptibility (CMS) Index. At increased heart rates (> 75 bpm), Agatston scores of the low mass calcification were similar to the reference score, while Agatston scores of the medium and high mass calcification increased significantly up to 50% for all CT systems. Threefold CMS increases at > 75 bpm in comparison with < 60 bpm were shown. For medium and high mass calcifications, significant differences in CMS between CT systems were found. Heart rate substantially influences CCS for high-end CT systems of four major manufacturers, but CT systems differ in motion susceptibility. Follow-up CCS CT scans should be acquired on the same CT system and protocol, and preferably with comparable heart rates.

Discordance between anatomical and functional coronary stenosis severity.

BACKGROUND.: New developments have made 16-slice multidetector computed tomography (MDCT) a promising technique for detecting significant coronary stenoses. At present, there is a paucity of data on the relation between fractional flow reserve (FFR) measurement and MDCT stenosis detection. OBJECTIVE.: The aim of this study was to investigate the relation between the anatomical severity of coronary artery disease detected by MDCT and functional severity measured by fractional flow reserve (FFR). METHODS.: We studied 53 patients (39 men and 14 women, age 62.5+/-8.1 years) with single-vessel disease scheduled for percutaneous coronary intervention (PCI). All patients underwent MDCT scanning one day prior to PCI and FFR was measured before PCI in the target vessel. RESULTS.: MDCT analysis could be performed in 52 of 53 patients (98.1%) and all patients had adequate FFR and quantitative coronary angiography (QCA) measurements. The mean stenosis diameters calculated by MDCT and QCA were 67.0+/-11.6% and 60.8+/-11.6% respectively. No significant relation was found between MDCT and QCA (r=0.22, p=0.12) The mean FFR in all patients was 0.67+/-0.18. A relation of r=-0.46 (p=0.0006) between QCA and FFR was found. In contrast, no relation between MDCT and FFR could be demonstrated (r=-0.09, p=0.50). Furthermore, a high incidence of false-positive and false-negative findings was present in both diagnostic modalities. CONCLUSION.: There is no clear relation between the anatomical and functional severity of coronary artery disease as defined by MDCT and FFR. Therefore, functional assessment of coronary artery disease remains mandatory for clinical decisionmaking. (Neth Heart J 2007;15:5-11.).

Influence of dose reduction and iterative reconstruction on CT calcium scores: a multi-manufacturer dynamic phantom study.

To evaluate the influence of dose reduction in combination with iterative reconstruction (IR) on coronary calcium scores (CCS) in a dynamic phantom on state-of-the-art CT systems from different manufacturers. Calcified inserts in an anthropomorphic chest phantom were translated at 20 mm/s corresponding to heart rates between 60 and 75 bpm. The inserts were scanned five times with routinely used CCS protocols at reference dose and 40 and 80% dose reduction on four high-end CT systems. Filtered back projection (FBP) and increasing levels of IR were applied. Noise levels were determined. CCS, quantified as Agatston and mass scores, were compared to physical mass and scores at FBP reference dose. For the reference dose in combination with FBP, noise level variation between CT systems was less than 18%. Decreasing dose almost always resulted in increased CCS, while at increased levels of IR, CCS decreased again. The influence of IR on CCS was smaller than the influence of dose reduction. At reference dose, physical mass was underestimated 3-30%. All CT systems showed similar CCS at 40% dose reduction in combinations with specific reconstructions. For some CT systems CCS was not affected at 80% dose reduction, in combination with IR. This multivendor study showed that radiation dose reductions of 40% did not influence CCS in a dynamic phantom using state-of-the-art CT systems in combination with specific reconstruction settings. Dose reduction resulted in increased noise and consequently increased CCS, whereas increased IR resulted in decreased CCS.

Echocardiographic and electron beam tomographic assessment of stenosis in patients with aortic valve disease: gradient versus valve area.

BACKGROUND: Transthoracic echocardiography (TTE) is routinely used to evaluate aortic valve stenosis. However, it does not give reliable results in every patient. There is growing interest in electron-beam tomography (EBT) as a noninvasive cardiac imaging technique. The usefulness of EBT to evaluate aortic stenosis has yet to be evaluated. AIM: To compare EBT with TTE in assessing severity of aortic stenosis. METHODS: In total 47 patients (18 females, 29 males) underwent a contrast-enhanced EBT scan and TTE within 6±20 days. The calcium score of the aortic valve was determined and the aortic valve area (AVA) was measured by planimetry. A complete TTE study, during which the peak pressure gradient across the aortic valve was measured, was performed in all patients by an experienced sonographer. RESULTS: There was a significant correlation between AVA assessed by EBT and peak pressure gradient (r=-0.38, p=0.009). The calcium score of the aortic valve assessed by EBT correlated with peak pressure gradient (r=0.48, p=0.001). CONCLUSION: EBT is a useful noninvasive method to evaluate the severity of aortic stenosis. It holds the possibility of assessing the AVA as well as quantification of the degree of calcification.

Human tissue valves in aortic position: determinants of reoperation and valve regurgitation.

BACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve regurgitation measured by serial echocardiography. METHODS AND RESULTS: In adult patients, 218 cryopreserved aortic allografts were implanted with the subcoronary (85) or the root replacement technique (133), and 81 patients had root replacement with a pulmonary autograft. Mean follow-up was 4.2 years (SD 2.7; range, 0 to 10.5). Patient age, operator experience with subcoronary implantation, and allograft diameter were independent predictors for reoperation. With repeated color Doppler echocardiography, the severity of aortic regurgitation was assessed by the jet length method and the jet diameter ratio. Multilevel hierarchical linear modeling was used to estimate initial aortic regurgitation (intercept), its change over time (slope), and the effect of 11 potential determinants of durability on aortic regurgitation. With the jet length method, the intercept was 0.94 grade and the slope was 0.11 grade per year. With the jet diameter ratio, the intercept was 0.34 and the annual increase was 0.01. Subcoronary implanted valves had more initial aortic regurgitation, but progression of aortic valve regurgitation did not differ from root replacement. At midterm follow-up, recipient age <40 years was the only independent predictor of aortic regurgitation. CONCLUSIONS: Subcoronary implantation has a learning curve, resulting in more initial aortic regurgitation and early reoperation compared with root replacement. In both techniques, progression of aortic regurgitation over time is small but accelerated in young adults.

Diagnostic Value of Urinary Steroid Profiling in the Evaluation of Adrenal Tumors.

Radiological examination may unexpectedly reveal an adrenal mass. Current algorithms for differentiating between benign and malignant lesions mainly rely on size and densitometry on unenhanced CT, which have limited specificity. We examined the diagnostic value of urinary steroid profiling by gas chromatography/mass-spectrometry (GC/MS) in differentiating between benign and malignant adrenal tumors. A retrospective study in two referral centers for patients with adrenal disease was performed. All urinary steroid profiles ordered for evaluation of an adrenal tumor between January 2000 and November 2011 were examined. Patients were diagnosed with adrenal cortical carcinoma (ACC), adrenal cortical adenoma (ACA), or other adrenal mass. Results of hormonal measurements, imaging studies, pathology reports, and clinical outcome were retrieved from medical records. The diagnostic value of individual urinary steroid metabolites was determined by receiver operating characteristics analysis. Cut-off values were compared to reference values from an age and gender-standardized population of healthy controls. Eighteen steroid metabolites were excreted in significantly higher concentrations in patients with ACC (n = 27) compared to patients with ACA (n = 107) or other adrenal conditions (n = 18). Tetrahydro-11-deoxycortisol (THS) at a cut-off value of 2.35 µmol/24 h differentiated ACC from other adrenal disorders with 100% sensitivity and 99% specificity. Elevated urinary excretion of THS was associated with a very high sensitivity and specificity to differentiate between an ACC and a benign adrenal mass. Urinary steroid profiling might be a useful diagnostic test for the evaluation of patients with an adrenal incidentaloma.

Subcoronary implantation or aortic root replacement for human tissue valves: sufficient data to prefer either technique?

The aortic root replacement technique with aortic allograft or pulmonary autograft might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. We explored the influence of the learning process on the incidence of reoperation and the severity of postoperative aortic regurgitation as assessed by color Doppler echocardiography. The subcoronary implantation technique was used in 81 patients, and root replacement was done in 63 patients. The first 30 patients of each group were considered as the surgeons' learning curve. Reoperations were more common in the subcoronary implantation group. After exclusion of early reoperations, the median regurgitation score based on echocardiographic examination was 0.22 in the first 30 patients from the subcoronary implantation group and 0.14 in the root replacement group. The subsequent patients from these groups had regurgitation scores of 0.20 and 0.17, respectively. Statistical analysis of these data showed no significant difference. This interim report suggests that the learning curve for the surgical procedure and the grouping of echocardiographic data influence the interpretation of follow-up studies. The superiority of either technique with regard to aortic regurgitation has yet to be proved.

Aortic allograft implantation techniques: pathomorphology and regurgitant jet patterns by Doppler echocardiographic studies.

BACKGROUND: The diagnosis of allograft-specific pathology by echocardiography has important consequences for patient counseling and research. This study describes the pathomorphologic findings and color Doppler jet patterns in a consecutive series of patients after allograft placement with either the subcoronary implantation or root replacement technique. METHODS: From 1987 to July 1996, the subcoronary allograft implantation technique and root replacement technique were used in 82 patients and 70 patients, respectively. These patients comprised the study group. RESULTS: The incidence of paravalvular leaks and eccentric regurgitant jets was higher with subcoronary implantation (41%) than with root replacement (11%). Patients with a subcoronary implanted allograft had a higher incidence of eccentric jets. CONCLUSIONS: These findings support the concept of preservation of valve geometry after root replacement, as allograft-specific pathomorphologic abnormalities and eccentric jets are more common after subcoronary implantation of allografts. Learning effects, however, cannot be excluded as the cause of these abnormalities.

Reproducibility of color Doppler flow quantification of aortic regurgitation.

The preferred method for quantification of aortic regurgitation severity with color Doppler echocardiography is the assessment of the ratio of jet diameter to left ventricular outflow tract diameter and jet area to left ventricular outflow tract area. However, the reproducibility of these measurements is not known and may limit its clinical application. This study was performed to identify sources of variability and reproducibility of the echocardiographic data. We examined 62 color Doppler echocardiographic examinations of patients showing isolated aortic regurgitation after human tissue valve implantation. The mean differences with standard deviations between paired measurements were calculated. The interobserver, intraobserver, and interframe variability showed a close agreement for the jet diameter and left ventricular outflow tract diameter measurements. The agreement for jet area and left ventricular outflow tract area measurements showed a small bias, but a large variance. The reproducibility of jet-left ventricular outflow tract diameter is better than the jet-left ventricular outflow tract area measurement and is more accurate to assess the severity of aortic regurgitation from color Doppler images.

Allograft reconstruction of the right ventricular outflow tract.

OBJECTIVE: Evaluation of allograft reconstruction of the right ventricular outflow tract (RVOT). METHODS: From 1986 to April 1995, 201 allografts (146 pulmonary, 55 aortic) were implanted in 189 patients for conduit reconstruction of the RVOT in congenital heart disease or in the pulmonary autograft procedure. The mean age at allograft implantation was 16 years (range 2 weeks - 54 years). The primary diagnoses of these patients were truncus arterious (n = 19, 10%), transposition of the great arteries (TGA) with ventricular septal defect (VSD) and pulmonary atresia (PA) or stenosis (PS) (n = 14, 7%), PA with VSD (n = 26, 14%), PA or PS with intact septum (n = 7, 4%), tetralogy of Fallot (n = 44, 23%), corrected TGA with PA or PS (n = 11, 6%), tricuspid atresia (n = 9, 5%), aortic valve pathology for pulmonary autograft procedure (n = 55, 29%), and miscellaneous (n = 4, 2%). The allograft implantation was a reoperation in 54 patients (29%). RESULTS: The mean follow-up was 2.5 years (range 4 weeks-9 years). Six patients died in hospital (3.2%). Patient survival at 5 years was 91% (95% CL 86-95%). Freedom from all valve-related events (2 deaths, 17 reoperations, one endocarditis), as determined during reoperation or autopsy at 5 years was 78% (95% CL 65-86%). Freedom from structural allograft failure was 83% (2 deaths, 12 reoperations, 95% CL 70-90%). Allografts implanted for congenital right heart defects failed earlier than allografts used for pulmonary autograft procedures (P = 0.05). Aortic allografts showed structural failure more often than pulmonary allografts (P = 0.05). There were more valve-related events in patients of a younger age at implantation (P = 0.02) and in those allograft valves from younger donors (P = 0.004). CONCLUSIONS: Allograft RVOT reconstruction is an adequate surgical therapy. The allograft should preferably be pulmonary. A younger age at implantation is a risk factor for allograft failure. Donor age may be a thus-far underestimated risk factor for allograft degeneration.

Aortic root replacement with a pulmonary autograft.

A series of 42 consecutive patients with exclusively aortic root replacement using the pulmonary autograft is presented. The mean age at operation was 19.3 years (range 0.3-41.4). Two patients died in hospital (4.8%; 70% CL: 0.0-8.2). This mortality was not related to the autograft procedure. The mean follow-up time was 30 months (range 3-70; SD: 20). Late mortality consisted of two patients; in one of these severe autograft failure occurred due to chronic juvenile rheumatoid arthritis. The estimated survival rate at 4 years was 88.8% (70% CL: 83.3-94.5). Morbidity involved three patients. One had a total heart block after operation, requiring pacemaker implantation and two patients were reoperated: one for severe autograft failure due to recurrent acute rheumatic fever and the other for severe stenosis at the distal anastomosis of the pulmonary allograft. Thromboembolic complications and endocarditis were not registered. Reoperations for technical or degenerative reasons were not necessary. The estimated event-free survival rate at 4 years was 78.7% (70% CL: 71.0-86.4). Serial echocardiography (n = 28) showed a significant increase of the autograft annulus diameter of 2.9 mm (SD: 2.7). Thirty-five of the 37 patients with an autograft in situ were in NYHA class I, and 2 in class II. At last follow-up precordial color Doppler echocardiography showed moderate aortic regurgitation in one patient and no, trivial or mild aortic regurgitation in 36 patients. Stenosis of the autograft was not observed. These medium-term results are promising with respect to mortality, morbidity and functional results.(ABSTRACT TRUNCATED AT 250 WORDS)