Recipient Size Matching Research Articles

Improved donor lung size matching by estimation of lung volumes based on chest X-ray measurements.

Organ size matching is an important determinant of successful allocation and outcomes in lung transplantation. While computed tomography (CT) is the gold standard, it is rarely used in an organ-donor context, and chest X-ray (CXR) may offer a practical and accurate solution in estimating lung volumes for donor and recipient size matching. We compared CXR lung measurementsto CT-measured lung volumes and traditional estimates of lung volume in the same subjects. Our retrospective study analyzed clinically obtained CXR and CT lung images of 250 subjects without evidence of lung disease (mean age 9.9 ± 7.8 years; 129 M/121F). From CT, each lung was semi-automatically segmented and total lung volumes were quantified. From anterior-posterior CXR view, each lung was manually segmented and areas were measured. Lung lengths from the apices to the mid-basal regions of each lung were measured from CXR. Quantified CT lung volumes were compared to the corresponding CXR lung lengths, CXR lung areas, height, weight, and predicted total lung capacity (pTLC). There are strong and significant correlations between CT volumes and CXR lung areas in the right lung (R2 = .89, p < .0001), left lung (R2 = .87, p < .0001), and combined lungs (R2 = .89, p < .0001). Similar correlations were seen between CT volumes and CXR measured lung lengths in the right lung (R2 = .79, p < .0001) and left lung (R2 = .81, p < .0001). This correlation between anatomical lung volume (CT) and CXR was stronger than lung-volume correlation to height (R2 = .66, p < .0001), weight (R2 = .43, p < .0001), or pTLC (R2 = .66, p < .0001). CXR measures correlate much more strongly with true lung volumes than height, weight, or pTLC. The ability to obtain efficient and more accurate lung volume via CXR has the potential to change our current listing practices of using height as a surrogate for lung size, with a case example provided.

Impact of Size Matching on Survival Post Heart Transplant in Infants: Estimated Total Cardiac Volume Ratio is Better Than Donor-Recipient Weight Ratio

<h3>Purpose</h3> Total Cardiac Volume (TCV) is a novel method of donor‒recipient size matching in pediatric heart transplantation (HT). However, usage of donor-recipient TCV ratio, instead of the donor-recipient weight ratio (DRWR) is still controversial. This study sought to determine whether estimated (e)TCV ratio is associated with infant post-transplant survival. <h3>Methods</h3> The United Network for Organ Sharing (UNOS) was used to search for infants (age: <1 year) who were listed for and received HT in 1987-2020. Donor and recipient eTCV were calculated from weight using previously published data. This equation is derived and validated from measured TCV in 140 donor-like CT scans. Cubic spline was used to determine optimal eTCV ratio range that significantly predicts survival. Patient cohort was divided according to the significant range and survival was compared. <h3>Results</h3> A total of 2864 infants were identified. The optimal eTCV ratio predictive of infant survival was 1.05-1.85. 70% (n=2166) patients had an optimal TCV ratio, while 16.7% (n=517) were in the lower (LR) and 5.9% (n=181) in the higher (HR) group. Kaplan-Meier analysis showed better survival for patients within the optimal vs LR (p<0.001), and similar survival compared to HR (p=0.08; figure). A 2-year conditional survival showed that LR had similar survival to the optimal group (p=0.76), and HR had worse survival than the other groups (optimal, p=0.002; LR p=0.02) (figure). Infants with optimal eTCV ratio (n=2166) had DRWR ranging from 1.09-5. Of these 33.6% had DRWR 2-3, and 5.8% DRWR>3. <h3>Conclusion</h3> Currently, an upper DRWR limit has not been established in infants. Therefore, the eTCV range determined is important since it identifies a potential upper limit that significantly predicts survival. This also implies that this finding can increase donor utilization since the eTCV range includes DRWR ranges that are frequently not used.

Evaluating the Use of CT-Derived Lung Volumes in Donor-Recipient Lung Size Matching for Lung Transplantation

<h3>Purpose</h3> Practices for donor and recipient size matching for lung transplantation vary. The objective of this study was to assess the accuracy of CT-derived lung volumes to predict donor-recipient lung size match for bilateral lung transplantation. <h3>Methods</h3> We studied 62 patients who underwent bilateral lung transplantation for Interstitial Lung Disease/Idiopathic Pulmonary Fibrosis during 2018-2019. Recipient data was retrieved from medical records and our transplant database. Donor data was obtained from UNOS DonorNet. Data collected included demographic data, lung heights, estimated donor total lung capacity (TLC) and recipient measured TLC from plethysmography; Computed Tomography (CT) derived lung volumes both pre- and post-transplant in recipients and clinical data. The recipient post-transplant CT-derived lung volume was used as a surrogate for donor lung CT volumes due to unavailable or poor donor data. Techniques included thresholding, region growing and cutting using Computer-Aided Design. Preoperative CT-derived lung volumes in recipients were compared with the plethysmography TLC, Frustum Model, and donor estimated TLC. We studied the ratio of recipient's pre- and post-operative CT-derived volumes, and the ratio of preoperative CT-derived lung volume and donor estimated TLC and correlated with one-year outcomes. <h3>Results</h3> The recipient preoperative CT-derived volume correlated with the recipient preoperative plethysmography TLC (Pearson correlation coefficient (PCC) of 0.688, p-value of 1.75e-07) and with the recipient Frustum model volume (PCC of 0.593, p-value of 2.766e-07). The recipient postoperative CT-derived volume correlated with the recipient postoperative plethysmography TLC (PCC of 0.651, p-value of 9.424e-06). There was no statistical correlation between recipient CT-derived preoperative or postoperative volume with donor estimated TLC. The ratio of preoperative CT-derived volume to donor estimated TLC correlated inversely with length of ventilation (p value: 0.0031). Lung oversizing (post- to preoperative CT lung volume ratio of over 1.2) did not affect outcomes. <h3>Conclusion</h3> CT-derived lung volume is a valid and convenient method for evaluating lung sizing for transplants. Donor estimated TLC should be interpreted cautiously. Matching donor and recipient CT lung volumes will be the scope of further research.

Association of Predicted Heart Mass from Mesa and Left Ventricular Mass from Dallas Heart Study with Heart Transplant Outcomes in the New Allocation System

<h3>Purpose</h3> Donor and recipient size matching remains an important component of donor selection in heart transplant (HT). One approach to size matching includes using predicted heart mass (PHM), derived from the Multi-ethnic Study of Atherosclerosis (MESA). Compared to MESA, the Dallas Heart Study (DHS) may better represent the U.S. donor pool. We examined the association of PHM from MESA and predicted left ventricular mass (PLVM) from DHS with HT outcomes in two eras. <h3>Methods</h3> Linear regression was used to model PLVM from DHS participants (n=1,746) with normal LV size and function on cardiac MRI and BMI < 35 kg/m². The DHS PLVM model included age, gender, height, weight and race. We then examined the association of DHS PLVM and MESA PHM with 1-year mortality post-HT in the United Network of Organ Sharing registry (Era 1: 2007-2016 and Era 2: 2018-2021) using Kaplan-Meier survival estimation and univariate Cox proportional hazards models stratified by presence or absence of low donor:recipient mass ratio (< 0.86). <h3>Results</h3> The DHS derivation cohort had a median age of 43 years, 40% self-identified as Black and 18% as Hispanic, 23% had HTN and 7% had DM. DHS PLVM and MESA PHM were significantly correlated (R=0.96, p < 0.001). There was no statistically significant difference in the distribution of donor-recipient mass ratios by DHS PLVM and MESA PHM across eras (Figure). In Era 1, a low DHS PLVM ratio was associated with worse 1-year mortality post-HT (p < 0.001), similar to the previously reported association with MESA PHM). However, in Era 2 neither DHS PLVM nor MESA PHM were associated with 1-year mortality [PLVM HR 0.9 (0.7-1.2) and PHM HR 1.1 (0.8-1.4)] (Figure). <h3>Conclusion</h3> In a contemporary cohort of HT recipients, neither PHM nor PLVM from DHS were associated with 1-year mortality post-HT. Additional donor and recipient factors such as mechanical circulatory support may be playing a larger role in HT outcomes in the current era.

Donor and Recipient Size Matching in Heart Transplantation With Predicted Heart and Lean Body Mass

Donor and recipient size matching during heart transplant can be assessed using weight or predicted heart mass (PHM) ratios. We developed sex-specific allomteric equations for PHM and predicted lean body mass (PLBM) using the United Kingdom Biobank (UKB) and evaluated their predictive value in the United Network of Organ Sharing database. Donor and recipient size matching was based on weight, PHM and PLBM ratios. PHM was calculated using the Multiethnic Study of Atherosclerosis and UKB equations. PLBM was calculated using the UKB and National Health and Nutrition Examination Survey equations. Relative prognostic utility was compared using multivariable Cox analysis, adjusted for predictors of 1-year survival in the Scientific Registry of Transplant Recipients model. Of 53,648 adult patients in the United Network of Organ Sharing database between 1996 and 2016, 6528 (12.2%) died within the first year. In multivariable analysis, undersized matches by any metric were associated with increased 1-year mortality (all P < 0.01). Oversized matches were at increased risk using PHM or PLBM (all P < 0.01), but not weight ratio. There were significant differences in classification of size matching by weight or PHM in sex-mismatched donor-recipient pairs. A significant interaction was observed between pulmonary hypertension and donor undersizing (hazard ratio 1.15, P = 0.026) suggesting increased risk of undersizing in pulmonary hypertension. Donor and recipient size matching with simplified PHM and PLBM offered an advantage over total body weight and may be more important for sex-mismatched donor-recipient pairs. Donor undersizing is associated with worse outcomes in patients with pulmonary hypertension.

A novel method of donor‒recipient size matching in pediatric heart transplantation: A total cardiac volume‒predictive model

The pediatric heart transplant community uses weight-based donor-to-recipient size matching almost exclusively, despite no evidence to validate weight as a reliable surrogate of cardiac size. Donor size mismatch is the second most common reason for the refusal of donor hearts in current practice (∼30% of all refusals). Whereas case-by-case segmentation of total cardiac volume (TCV) by computed tomography (CT) for direct virtual transplantation is an attractive option, it remains limited by the unavailability of donor chest CT. We sought to establish a predictive model for donor TCV on the basis of anthropomorphic and chest X-ray (CXR) cardiac measures. Banked imaging studies from 141 subjects with normal CT chest angiograms were obtained and segmented using 3-dimensional modeling to derive TCV. CXR data were available for 62 of those subjects. A total of 3 predictive models of TCV were fit through multiple linear regression using the following variables: Model A (weight only); Model B (weight, height, sex, and age); Model C (weight, height, sex, age, and 1-view anteroposterior CXR maximal horizontal cardiac width). Model C provided the most accurate prediction of TCV (optimism corrected R2 = 0.99, testing set R2 = 0.98, mean absolute percentage error [MAPE] = 8.6%) and outperformed Model A (optimism corrected R2 = 0.94, testing set R2 = 0.94, MAPE = 16.1%) and Model B (optimism corrected R2 = 0.97, testing set R2 = 0.97, MAPE = 11.1%). TCV can be predicted accurately using readily available anthropometrics and a 1-view CXR from donor candidates. This simple and scalable method of TCV estimation may provide a reliable and consistent method to improve donor size matching.

Donor-recipient predicted heart mass ratio and right ventricular-pulmonary arterial coupling in heart transplant.

Right ventricular-pulmonary arterial (RV-PA) coupling interactions are largely unexplored in heart transplant patients. The outcome of this study was RV-PA coupling at 7 and 30 days after heart transplant and its association with donor-recipient size matching. Clinical, echocardiographic and haemodynamic data from a retrospective cohort of heart transplant recipients and respective donors were reviewed. Coupling between RV-PA was examined by assessing the RV fractional area change and pulmonary artery systolic pressure ratio. Donor-recipient size matching was assessed by the predicted heart mass (PHM) ratio, and groups with a PHM ratio <1 and ≥1 were compared. Forty-four heart transplant recipients were included in this study (50 years, 57% male sex). Postoperative RV-PA coupling improved from 7 to 30 days (RV fractional area change/pulmonary artery systolic pressure 0.9 ± 0.3 vs 1.2 ± 0.3; P < 0.001). A positive association was found between an adequate PHM ratio and improvement of RV fractional area change/pulmonary artery systolic pressure at 30 days, independent of graft ischaemic time and pre-existent pulmonary hypertension (B coefficient 0.54; 95% confidence interval 0.11-0.97; P = 0.016; adjusted R2 = 0.24). These findings highlight the role of PHM as a metric to help donor selection and suggest its impact in RV-PA coupling interactions post-heart transplant.

Novel Methods for Donor and Recipient Size Matching in Heart Transplantation

Heart donor and recipient size matching is associated with improved post-transplant outcomes. Many programs use total body weight ratios, which do not account for body composition or heart specific mass. We derived equatinos for lean body mass (LBM) and predicted heart mass (PHM) in the UK Biobank (UKB), and determined associations with survival using the United Network for Organ Sharing (UNOS) database. We derived LBM and PHM equations from 2846 participants in the UKB who underwent cardiac MRI and dual-energy X-ray absorptiometry for body composition analysis. Prognostic utility was validated in adults patients in the UNOS database between January 1996 and November 2017. Donor-recipient size matching was based on five methods: weight ratio, two methods for LBM ratio (National Health and Nutrition Examination Survey [NHANES] and UKB) and two methods for PHM ratios (Multi-ethnic Study of Atherosclerosis [MESA] and UKB). Relative prognostic utility was compared using multivariable Cox analysis adjusted for variables in the SRTR one year patient survival equation. Donor-recipient matching was defined as < 0.8 (undersized), 0.8 to 1.2 (matched) or > 1.2 (oversized). In the validation cohort, 6528 of 53,648 patients (12.2%) died within the first year. In multivariable analysis, undersized matches were associated with increased one-year mortality for all methods (p<0.01). Oversized matches by LBM or PHM ratios (adjusted HR 1.08 - 1.15, all p<0.05) were also associated with increased one-year mortality. Donor oversizing by UKB LBM was associated with worse outcomes in female donors to male recipients (Figure, interaction p=0.001). Significant under or oversizing of donor hearts, predicted using either of LBM or PHM algorithms, was associated with worse one-year survival following cardiac transplantation. Donor-recicipient sex mismatches should also be considered when using LBM and PHM based ratios.

Volumetrics and fit assessments for donor to recipient size matching in pediatric heart transplantation: Is it time for a new paradigm?

Pediatric heart transplant patients face the highest waitlist mortality in solid organ transplantation. Given the relatively fixed number of donor organs becoming available each year, improving donor organ utilization could potentially have significant impact on reducing waitlist mortality. Donor to recipient weight ratio has historically been used to identify suitable donors; however, this method does not take into account the potential for significant variance in heart size due to complex congenital heart disease or underlying cardiomyopathy. We believe, based on our experience to date, that donor matching based upon weight ratios should be augmented by improved methodologies that provide a more accurate assessment of heart volumes. Herein we describe the rationale for these methodologies and our single-center experience using volumetrics as an alternative for donor fit assessments.

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Twenty-second pediatric heart transplantation report – 2019; Focus theme: Donor and recipient size match

This continues to be an exciting time for pediatric heart transplantation. Since the first orthotopic heart transplantation a little over 50 years ago, the field has grown tremendously, including many advancements in the application of this therapy to children. Today, heart transplantation is performed routinely in many pediatric centers throughout the world with over 100 centers reporting to the International Thoracic Transplant Registry (Figure 1, eSlide H(p) 4). The Registry is the largest source of worldwide data on pediatric heart transplantation with over 14,000 transplants reported in children. The focus theme for this year's report is donor and recipient size match.

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-sixth adult heart transplantation report — 2019; focus theme: Donor and recipient size match

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-sixth adult heart transplantation report — 2019; focus theme: Donor and recipient size match

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-sixth adult lung and heart–lung transplantation Report—2019; Focus theme: Donor and recipient size match

This thirty-sixth adult lung and heart–lung transplant report summarizes data from 69,200 adult lung and 4,128 adult heart-lung transplants performed through June 30, 2018 and reported to the International Thoracic Organ Transplant Registry. With each year's report, we now provide more detailed analyses on a particular focus theme important to patient outcomes. Since 2013, these have been donor and recipient age; retransplantation; early graft failure; indication for transplant; allograft ischemic time; and multiorgan transplantation. Although widely accepted as critical to decision making at the time of receipt of an organ donor offer, there is surprisingly little literature outlining current practice and the impact of size (mis-)matching on outcomes. Hence this year's report focuses on an overall theme of donor and recipient size matching. In addition to reporting donor and recipient height and weight difference for all adult lung and heart-lung transplant recipients stratified by transplant type (bilateral or single) and indication, we report historical trends and associations between size match and survival. The Registry's online slide sets include results from additional analyses and complementary information not included in this publication (see https://ishltregistries.org/registries/slides.asp ).

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Twenty-second pediatric lung and heart-lung transplantation report—2019; Focus theme: Donor and recipient size match

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Twenty-second pediatric lung and heart-lung transplantation report—2019; Focus theme: Donor and recipient size match

Impact of Donor to Recipient Size Match on Survival after Heart Transplant Bridged with Continuous Flow Left Ventricular Assist Device

Purpose Heart transplant for patients with left ventricular assist device (LVAD) often requires long cardiopulmonary bypass and increased blood product use. Hypothesis was made that a donor heart should not be undersized so that it can tolerate complicated surgery. We evaluated the impact of donor-to-recipient size matching on outcome after heart transplantation bridged with LVAD. Methods We reviewed UNOS registry data on patients who received heart transplant bridged with continuous flow LVAD (CF-LVAD). Patients were divided into three groups based on donor and recipient weight ratio; 1.2 (Oversized group). Pre-Transplant characteristics were compared among the groups. The primary outcome was post-transplant survival. Secondary outcomes included graft failure, dialysis requirement post-transplant and stroke. Kaplan-Meier survival curves and the log-rank test was used to predict and compare survival among 3 groups. Cox proportional hazards analysis was used to identify independent predictors of mortality. Results From 2009 to 2015, 4020 patients were bridged to heart transplant with CF-LVAD. Undersized group included 586 patients (14.6%), Matched group included 2699 patients (67.1%) and Oversized group included 735 patients (18.3%). Incidence of post-transplant dialysis was higher in Undersized group (16%) than Matched (11.8%) or Oversized group (10%, p=0.003). Incidence of graft failure was significantly greater in Undersized group (18%) than Matched (13.4%) or Oversized group (15%, p=0.019). On univariate analysis survival of Undersized group was lower than other two groups (p=0.022). Pre-transplant serum creatinine (p=0.001), height (0.002) and weight (p=0.007) were independent predictors of mortality but use of undersized heart was not. Conclusion Survival of heart transplant recipients of undersized donor is lower than that of size matched or oversized donor. Pre-transplant serum creatinine, height and weight were predictors of mortality but use of undersized heart itself was not.

(1241) - CT Derived Estimates of Total Lung Volume in Transplant Candidates: Can We Do without Plethysmography?

Lung Donor to recipient size matching is based on recipient's predicted Total Lung Capacity (TLC) adjusted for their actual TLC as measured by nitrogen washout (TLC-N2) or body box plethysmography (TLC-BB). However, many lung transplant (LT) candidates with end stage disease can't perform the manoeuvres required for pulmonary function tests (PFTs). As all candidates undergo thoracic CT scans during LT workup, we assessed utility of CT derived estimates of total lung volume (TLV-CT) as a surrogate of TLC.

Donor–recipient size matching and mortality in heart transplantation: Influence of body mass index and gender

The International Society for Heart and Lung Transplantation (ISHLT) guidelines advise against inappropriate weight match (IWM) for heart transplant, defined as donor weight <70% of recipient's weight. Few studies have explored in detail this size-matching recommendation, especially with regard to body mass index (BMI) and gender matching. We aimed to determine whether any difference could be observed between size-matching in obese and non-obese recipients with regard to mortality after cardiac transplantation. Data from 52,455 adult heart transplants (recipients ≥18 years of age) between 1994 and 2013 were obtained from the ISHLT Registry. We defined the following subgroups of patients based on BMI: underweight, BMI <18.5; non-obese, BMI 18.5 to 30; and obese, BMI >30. The end-points were all-cause 30-day mortality and cumulative mortality. IWM was associated with increased 30-day mortality (odds ratio [OR] = 1.20, 95% confidence interval [CI] 1.01 to 1.43, p = 0.041) and cumulative mortality (hazard ratio [HR] = 1.14, 95% CI 1.07 to 1.22, p < 0.001). In non-obese recipients, IWM was associated with increased 30-day mortality (OR = 1.89, 95% CI 1.48 to 2.41, p < 0.001) as well as cumulative mortality (HR = 1.27, 95% CI 1.15 to 1.41, p < 0.001), whereas, for obese recipients, IWM was not associated with 30-day or cumulative mortality. Male recipients of female allografts (HR = 1.08, 95% CI 1.04 to 1.12, p < 0.001) as well as female recipients of male allografts (HR = 1.07, 95% CI 1.02 to 1.13, p = 0.003) had increased cumulative mortality compared with gender-matched transplants. There was no interaction between IWM and gender mismatch. Our results indicate that donor weight <70% of recipient weight increases mortality in non-obese heart transplant recipients, but not in obese transplant recipients. Gender mismatch increases mortality independently of weight match.

A novel objective method for deceased donor and recipient size matching in liver transplantation.

Although the consequences of implantation of a large whole liver graft into a small recipient such as compression and compromise of graft perfusion are well known, no accepted measure to aid in donor-to-recipient size matching exists. Donor liver graft and recipient native liver weights as well as donor and recipient size and amount of ascites were investigated in 1953 patients who underwent liver transplantation using deceased donor grafts between January 2002 and July 2013. We used a previously described formula for liver resections (standardized total liver volume [sTLV] = -794.41 + 1267.28 × body surface area [m(2)]) for calculating sTLV, in the current cohort of deceased liver donors. Early allograft dysfunction (EAD) and graft survival were the primary outcome measures. The formula for calculating sTLV for liver resections was validated as an accurate predictor of liver volume in the current cohort of deceased liver donors (r(2) = 0.45; P < 0.001). A cutoff point of sTLV ratio ≥ 1.25 was determined through receiver operating characteristic curves, and patients were dichotomized into 2 groups. In the sTLV ratio ≥ 1.25 group, 50% of patients developed EAD compared to 25% of patients in the sTLV ratio < 1.25 group (P < 0.001). The proportion of patients developing graft failure within 90 days was 9.6% in the sTLV ratio ≥ 1.25 group and 5.4% in the sTLV ratio < 1.25 group (P = 0.045). This study validates the use of the sTLV for prediction of actual donor liver weight in the transplant setting. Using this formula, donors with a calculated sTLV size ratio ≥ 1.25 have an increased risk of EAD and therefore caution should be used when that value is exceeded. This adjusted size ratio can be used as a decision aid when considering donor and recipient matching with potential liver organ offers.

Donor–Recipient Size Matching and Survival after Lung Transplantation. A Cohort Study

The association between a high predicted total lung capacity (pTLC) ratio (equal to pTLC(donor)/pTLC(recipient)), suggestive of an oversized allograft, with improved survival after lung transplantation (LTx) remains controversial. To characterize donor-recipient lung size matching based on the pTLC ratio and to investigate the relationship of the pTLC ratio with post-LTx survival. All subjects in the Scientific Registry of Transplant Recipients, who underwent first-time LTx in the lung allocation score-based system between May 4, 2005 and March 31, 2012, were studied, and the pTLC ratio was calculated on the basis of sex, height, and age. Risk of death after LTx was analyzed using Cox proportional hazards models. The pTLC ratio was available for 10,289 of the 10,318 study subjects (99.7%). The mean pTLC ratio was 1.015 ± 0.175 (interquartile range, 0.918-1.119). Univariate analysis showed that the pTLC ratio was strongly associated with death in the first LTx year (P < 0.0001). With the pTLC ratio entered as a spline there was a nonlinear association with declining risk of death with higher pTLC ratio from 0.5 to about 1.3, where an inflection occurred with rising risk at higher values. Accounting for the pTLC ratio, recipient and donor sex were not independently associated with death after LTx. A change of pTLC ratio from 0.918 to 1.119 (the interquartile range) was associated with similar point estimates of reduced risk of death at 1 year in univariate (hazard ratio, 0.78) and comprehensive risk-adjusted multivariate models (hazard ratio, 0.86). The pTLC ratio is an independent predictor of death in the first year after LTx and explains the association of sex with survival after LTx. Incorporating the pTLC ratio in the lung allocation mechanism could improve outcomes after LTx.

Clamshell Incision vs. Sternal-Sparing Incision in Lung Transplantation

Purpose Transverse thoracosternotomy, or ‘clamshell’ incision, has been regarded as the incision of choice for bilateral lung transplantation (LTx) for the past decade. However, the clamshell incision can result in significant morbidity including sternal wound dehiscence, sternal instability, wound infection and pain. Bilateral anterior thoracotomy, which avoids transection of the sternum, has been proposed as an alternative. We assessed the safety and efficacy of bilateral anterior thoracotomy compared with the clamshell incision. Methods and Materials Single center retrospective review of 130 bilateral LTx patients operated January 2009-May 2012. 79/130 (61%) underwent clamshell incisions (Group A) (Median follow up time: 866 days) and 51/130 (39%) underwent sternal-sparing incisions (Group B) (Median follow up time: 699 days). Operative approach was allocated according to surgeon preference based on patient factors (diagnosis, body mass index, past surgery) and non-patient factors (donor ischaemic time, donor lung to recipient lung size match). Results 14/79 (18%) Group A patients developed sternal wound infection while 8/79 (10%) had sternal healing complications (10%). There was only one wound infection in Group B (chi-square, p=0.006). Median, (interquartile range) postoperative inpatient stay was comparable between groups (Group A vs Group B = 17 days, (13 – 30) vs. 15 days (11-25), as was ICU stay: 5.5 days (3-12) vs. 4 days (2-11 days ). No significant difference was found between groups in median (interquartile range) transplant duration:7 hours (5-8) vs. 7 hours (6–8), perfusion time: 209 hours ( 168 – 255) vs. 220 (191–247), or lung function at 1 year viz: VC% (mean±SD)= 87±19 vs. 92±23, median (interquartile range) FEV%= 81 (73–98) vs. 94 (66–105), FEV1/FVC = 0.79 (0.72–0.87) vs. 0.83 (0.71–0.91 ). Conclusions Sternal-sparing incisions performed for bilateral LTx are associated with a lower rate of wound infection and healing complications than clamshell incisions. Surgery times, ICU bed days and functional outcomes were comparable.

MRI validated echocardiographic technique to measure total cardiac volume: A tool for donor–recipient size matching in pediatric heart transplantation

Our aim is to develop and validate an accurate method for estimating TCV using standard echocardiographic imaging that can be easily employed to aid in donor-recipient size matching in pediatric heart transplantation. Thirty patients who underwent Echo and cardiac magnetic resonance imaging (cMRI) were identified. TCV was measured on cMRI. TCV was determined echocardiographically by two methods: a volume measurement using the modified Simpson's method on a four-chamber view of the heart; and a calculated volume measurement which assumed a true-elliptical shape of the heart. These two methods where compared with the value obtained by cMRI using the concordance correlation coefficient (CCC). TCV by method 1 correlated well with cMRI (CCC=0.98%, CI=0.97, 0.99). TCV by method 2 had a CCC=0.90 (CI=0.9464, 0.9716) when compared to cMRI. Left ventricular end-diastolic volume (LVEDV) also correlated as a predictor of TCV in patients with structurally normal hearts and could be described by the equation: TCV=6.6 (LVEDV)+12 (R(2) =0.97). Echocardiographic assessment of TCV for recipients and their potential donors is a simple process and can be prospectively applied as part of donor evaluation.