Outcomes and treatment strategy of transcatheter aortic valve replacement with balloon-expandable valve in borderline-size annulus

BACKGROUND

Candidates for transcatheter aortic valve replacement (TAVR) occasionally have a "borderline-size" aortic annulus between 2 transcatheter heart valve sizes, based on the manufacturer's sizing chart. Data on TAVR outcomes in such patients are limited.

METHODS

We retrospectively reviewed 1816 patients who underwent transfemoral-TAVR with balloon-expandable valve (BEV) at our institution between 2016 and 2020. We divided patients into borderline and non-borderline groups based on computed tomography-derived annular measurements and compared outcomes. Furthermore, we analyzed procedural characteristics and compared outcomes between the smaller- and larger-valve strategies in patients with borderline-size annulus.

RESULTS

During a median follow-up of 23.3 months, there was no significant difference between the borderline (n = 310, 17.0 %) and non-borderline (n = 1506) groups in mortality (17.3 % vs. 19.5 %; hazard ratio [HR] = 0.86 [95% CI = 0.62-1.20], p = 0.39), major adverse cardiac/cerebrovascular events (MACCE: death/myocardial infarction/stroke, 21.2 % vs. 21.5 %; HR = 0.97 [0.71-1.32], p = 0.85), paravalvular leak (PVL: mild 21.8 % vs. 20.6 %, p = 0.81; moderate 0 % vs. 1.2 %; p = 0.37), or mean gradient (12.9 ± 5.8 vs. 12.6 ± 5.2 mmHg, p = 0.69) at 1 year. There was no significant difference between the larger-(n = 113) and smaller-valve(n = 197) subgroups in mortality (23.7 % vs. 15.2 %; HR = 1.57 [0.89-2.77], p = 0.12), MACCE (28.1 % vs. 18.4 %; HR = 1.52 [0.91-2.54], p = 0.11), mild PVL (13.3 % vs. 25.9 %; p = 0.12), or mean gradient (12.3 ± 4.5 vs. 13.6 ± 5.3 mmHg, p = 0.16); however, the rate of permanent pacemaker implantation (PPI) was higher in the larger-valve subgroup (15.9 % vs. 2.6 %, p < 0.001).

CONCLUSION

Borderline-size annulus is not associated with higher risk of adverse outcomes after BEV-TAVR. However, the larger-valve strategy for borderline-size annulus is associated with higher PPI risk, suggesting a greater risk of injury to the conduction system.

Intermittent Ex Vivo Lung Perfusion in a Porcine Model for Prolonged Lung Preservation

BACKGROUND

Ex vivo lung perfusion expands the lung transplant donor pool and extends preservation time beyond cold static preservation. We hypothesized that repeated regular ex vivo lung perfusion would better maintain lung grafts.

METHODS

Ten pig lungs were randomized into 2 groups. The control underwent 16 h of cold ischemic time and 2 h of cellular ex vivo lung perfusion. The intermittent ex vivo lung perfusion group underwent cold ischemic time for 4 h, ex vivo lung perfusion (first) for 2 h, cold ischemic time for 10 h, and 2 h of ex vivo lung perfusion (second). Lungs were assessed, and transplant suitability was determined after 2 h of ex vivo lung perfusion.

RESULTS

The second ex vivo lung perfusion was significantly associated with better oxygenation, limited extravascular water, higher adenosine triphosphate, reduced intraalveolar edema, and well-preserved mitochondria compared with the control, despite proinflammatory cytokine elevation. No significant difference was observed in the first and second perfusion regarding oxygenation and adenosine triphosphate, whereas the second was associated with lower dynamic compliance and higher extravascular lung water than the first. Transplant suitability was 100% for the first and 60% for the second ex vivo lung perfusion, and 0% for the control.

CONCLUSIONS

The second ex vivo lung perfusion had a slight deterioration in graft function compared to the first. Intermittent ex vivo lung perfusion created a better condition for lung grafts than cold static preservation, despite cytokine elevation. These results suggested that intermittent ex vivo lung perfusion may help prolong lung preservation.

Impact of untreated chronic obstructive coronary artery disease on outcomes after transcatheter aortic valve replacement

BACKGROUND AND AIMS

In transcatheter aortic valve replacement (TAVR) recipients, the optimal management of concomitant chronic obstructive coronary artery disease (CAD) remains unknown. Some advocate for pre-TAVR percutaneous coronary intervention, while others manage it expectantly. The aim of this study was to assess the impact of varying degrees and extent of untreated chronic obstructive CAD on TAVR and longer-term outcomes.

METHODS

The authors conducted a retrospective cohort study of TAVR recipients from January 2015 to November 2021, separating patients into stable non-obstructive or varying degrees of obstructive CAD. The major outcomes of interest were procedural all-cause mortality and complications, major adverse cardiovascular events, and post-TAVR unplanned coronary revascularization.

RESULTS

Of the 1911 patients meeting inclusion, 75%, 6%, 10%, and 9% had non-obstructive, intermediate-risk, high-risk, and extreme-risk CAD, respectively. Procedural complication rates overall were low (death 0.4%, shock 0.1%, extracorporeal membrane oxygenation 0.1%), with no difference across groups. At a median follow-up of 21 months, rates of acute coronary syndrome and unplanned coronary revascularization were 0.7% and 0.5%, respectively, in the non-obstructive population, rising in incidence with increasing severity of CAD (P < .001 for acute coronary syndrome/unplanned coronary revascularization). Multivariable analysis did not yield a significantly greater risk of all-cause mortality or major adverse cardiovascular events across groups. One-year acute coronary syndrome and unplanned coronary revascularization rates in time-to-event analyses were significantly greater in the non-obstructive (98%) vs. obstructive (94%) subsets (Plog-rank< .001).

CONCLUSIONS

Transcatheter aortic valve replacement can be performed safely in patients with untreated chronic obstructive CAD, without portending higher procedural complication rates and with relatively low rates of unplanned coronary revascularization and acute coronary syndrome at 1 year.

The degree of permanent pacemaker dependence and clinical outcomes following transcatheter aortic valve implantation: implications for procedural technique

Aims

Conduction abnormalities necessitating permanent pacemaker (PPM) implantation remain the most frequent complication post-transcatheter aortic valve implantation (TAVI), yet reliance on PPM function varies. We evaluated the association of right-ventricular (RV)-stimulation rate post-TAVI with 1-year major adverse cardiovascular events (MACE) (all-cause mortality and heart failure hospitalization).

Methods and results

This retrospective cohort study of patients undergoing TAVI in two high-volume centers included patients with existing PPM pre-TAVI or new PPM post-TAVI. There was a bimodal distribution of RV-stimulation rates stratifying patients into two groups of either low [≤10%: 1.0 (0.0, 3.6)] or high [>10%: 96.0 (54.0, 99.9)] RV-stimulation rate post-TAVI. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated comparing MACE in patients with high vs. low RV-stimulation rates post-TAVI. Of 4659 patients, 408 patients (8.6%) had an existing PPM pre-TAVI and 361 patients (7.7%) underwent PPM implantation post-TAVI. Mean age was 82.3 ± 8.1 years, 39% were women. A high RV-stimulation rate (>10%) development post-TAVI is associated with a two-fold increased risk for MACE [1.97 (1.20, 3.25), P = 0.008]. Valve implantation depth was an independent predictor of high RV-stimulation rate [odds ratio (95% CI): 1.58 (1.21, 2.06), P=<0.001] and itself associated with MACE [1.27 (1.00, 1.59), P = 0.047].

Conclusion

Greater RV-stimulation rates post-TAVI correlate with increased 1-year MACE in patients with new PPM post-TAVI or in those with existing PPM but low RV-stimulation rates pre-TAVI. A shallower valve implantation depth reduces the risk of greater RV-stimulation rates post-TAVI, correlating with improved patient outcomes. These data highlight the importance of a meticulous implant technique even in TAVI recipients with pre-existing PPMs.

Comparison of Outcomes Following Transcatheter Aortic Valve Replacement Requiring Peripheral Vascular Intervention or Alternative Access

Background Peripheral vascular intervention (PVI) is occasionally required to facilitate delivery system insertion or to treat vascular complications during transfemoral transcatheter aortic valve replacement (TF-TAVR). However, the impact of PVI on outcomes is not well understood. Therefore, we aimed to compare outcomes between TF-TAVR with versus without PVI and between TF-TAVR with PVI versus non-TF-TAVR. Methods and Results We retrospectively reviewed 2386 patients who underwent TAVR with a balloon-expandable valve at a single institution from 2016 to 2020. The primary outcomes were death and major adverse cardiac/cerebrovascular event (MACCE), defined as death, myocardial infarction, or stroke. Of 2246 TF-TAVR recipients, 136 (6.1%) required PVI (89% bailout treatment). During follow-up (median 23.0 months), there were no significant differences between TF-TAVR with and without PVI in death (15.4% versus 20.7%; adjusted HR [aHR], 0.96 [95% CI, 0.58-1.58]) or MACCE (16.9% versus 23.0%; aHR, 0.84 [95% CI, 0.52-1.36]). However, compared with non-TF-TAVR (n=140), TF-TAVR with PVI carried significantly lower rates of death (15.4% versus 40.7%; aHR, 0.42 [95% CI, 0.24-0.75]) and MACCE (16.9% versus 45.0%; aHR, 0.40 [95% CI, 0.23-0.68]). Landmark analyses demonstrated lower outcome rates following TF-TAVR with PVI than non-TF-TAVR both within 60 days (death 0.7% versus 5.7%, P=0.019; MACCE 0.7% versus 9.3%; P=0.001) and thereafter (death 15.0% versus 38.9%, P=0.014; MACCE 16.5% versus 41.3%, P=0.013). Conclusions The need for PVI during TF-TAVR is not uncommon, mainly due to the bailout treatment for vascular complications. PVI is not associated with worse outcomes in TF-TAVR recipients. Even when PVI is required, TF-TAVR is associated with better short- and intermediate-term outcomes than non-TF-TAVR.

One-year clinical and echocardiographic outcomes of transcatheter aortic valve replacement with SAPIEN 3 Ultra versus SAPIEN 3

BACKGROUND

The newest-generation balloon-expandable valve, SAPIEN 3 Ultra (S3U), is expected to function well with the enhanced sealing skirt compared with SAPIEN 3 (S3). However, current literature on the comparison between these two valves is limited to short-term follow-ups. Therefore, we aimed to evaluate the 1-year outcomes and echocardiographic changes of S3U compared with S3.

METHODS

We retrospectively identified patients who underwent transfemoral-transcatheter aortic valve replacement with S3U or S3 (20/23/26 mm) at our institution in 2018-2020. Outcomes were 1-year clinical events and echocardiographic parameters, and were compared between S3U and S3 after adjustment with inverse probability of treatment weighting.

RESULTS

The S3U and S3 groups included 297 (25.7%) and 858 (74.3%) patients, respectively. There were no significant differences between the two groups in clinical events (death 5.8% vs. 5.5%, hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.81-1.90; death or heart failure hospitalization 10.3% vs. 10.1%, HR 1.04, 95% CI 0.67-1.62). The S3U group had a lower prevalence of mild paravalvular leakage (PVL) (13.7% vs. 22.3%, p = 0.044), with similar moderate PVL (0.7% vs. 1.2%, p > 0.99). No significant differences were observed in aortic valve mean gradient and Doppler velocity index at 1 year. However, the S3U group had a larger increase in mean gradient from implantation to 1 year (median +4.70 vs. +1.63 mmHg, p < 0.001).

CONCLUSIONS

S3U and S3 carried similarly favorable clinical event risks. Nonetheless, S3U was associated with less frequent mild PVL but a larger increase in transprosthetic gradient. Further studies are needed to determine the prognostic impact of these hemodynamic differences.

Cerebral embolic protection and severity of stroke following transcatheter aortic valve replacement

BACKGROUND

The cerebral embolic protection (CEP) device captures embolic debris during transcatheter aortic valve replacement (TAVR). However, the impact of CEP on stroke severity following TAVR remains unclear. Therefore, we aimed to examine whether CEP was associated with reduced severity of stroke following TAVR.

METHODS

This was a retrospective cohort study of 2839 consecutive patients (mean age: 79.2 ± 9.5 years, females: 41.5%) who underwent transfemoral TAVR at our institution between 2013 and 2020. We categorized patients into Sentinel CEP users and nonusers. Neuroimaging data were reviewed and the final diagnosis of a cerebrovascular event was adjudicated by a neurologist blinded to the CEP use or nonuse. We compared the incidence and severity (assessed by the National Institutes of Health Stroke Scale [NIHSS]) of stroke through 72 h post-TAVR or discharge between the two groups using stabilized inverse probability of treatment weighting (IPTW) of propensity scores.

RESULTS

Of the eligible patients, 1802 (63.5%) received CEP during TAVR and 1037 (36.5%) did not. After adjustment for patient characteristics by stabilized IPTW, the rate of overall stroke was numerically lower in CEP users than in CEP nonusers, but the difference did not reach statistical significance (0.49% vs. 1.18%, p = 0.064). However, CEP users had significantly lower rates of moderate-or-severe stroke (NIHSS ≥ 6: 0.11% vs. 0.69%, p = 0.013) and severe stroke (NIHSS ≥ 15: 0% vs. 0.29%, p = 0.046). Stroke following CEP use (n = 8), compared with stroke following CEP nonuse (n = 15), tended to carry a lower NIHSS (median [IQR], 4.0 [2.0-7.0] vs. 7.0 [4.5-19.0], p = 0.087). Four (26.7%) out of 15 patients with stroke following CEP nonuse died within 30 days, with no death after stroke following CEP use.

CONCLUSIONS

CEP use may be associated with attenuated severity of stroke despite no significant difference in overall stroke incidence compared with CEP nonuse. This finding is considered hypothesis-generating and needs to be confirmed in large prospective studies.

Effect of Myocardial Tissue Characterization Using Native T1 to Predict the Occurrence of Adverse Events in Patients With Chronic Kidney Disease and Severe Aortic Stenosis

Among patients with chronic kidney disease (CKD), aortic stenosis (AS) is associated with a significantly higher rate of mortality. We aimed to evaluate whether diffuse myocardial fibrosis, determined using native T1 mapping, has prognostic utility in predicting major adverse cardiovascular events (MACEs), including all-cause mortality or heart failure hospitalization, in patients with CKD and severe AS who are evaluated for transcatheter aortic valve implantation. Cardiac magnetic resonance with T1 mapping using the modified Look-Locker inversion recovery technique was performed in 117 consecutive patients with severe AS and CKD (stage ≥3). Patients were followed up to determine the occurrence of MACE. The mean age of the 117 patients in the cohort was 82 ± 8 years. Native T1 was 1,055 ms (25th- to 75th percentiles 1,031 to 1,078 ms), which is higher than previously reported in healthy controls. Patients with higher T1 times were more likely to have higher N-terminal pro-B-type natriuretic peptide levels (4,122 [IQR 1,578 to 7,980] pg/ml vs 1,678 [IQR 493 to 2,851] pg/ml, p = 0.005) and a history of heart failure (33% vs 9%, p = 0.034). After median follow-up of 3.4 years, MACE occurred in 71 patients (61%). The Society of Thoracic Surgeons predicted risk of mortality score (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.02 to 1.12, p = 0.006), native T1 >1,024 ms (HR 2.10, 95% CI 1.09 to 4.06, p = 0.028), and New York Heart Association class (HR 1.56, 95% 1.09 to 2.34, p = 0.016) were independent predictors of MACE. Longer native T1 was associated with MACE occurrence in patients with CKD and severe AS.

Conduction Disturbance, Pacemaker Rates, and Hospital Length of Stay Following Transcatheter Aortic Valve Implantation with the Sapien 3 Valve

Background

In the absence of randomized data, an expert panel recently proposed an algorithm for conduction disturbance management in transcatheter aortic valve implantation (TAVI) recipients. However, external validations of its recommendations are limited.

Methods

We retrospectively identified 808 patients without a pre-existing pacing device who underwent transfemoral TAVI with the Sapien 3 valve at our institution in 2018-2019. Patients were grouped based on pre-existing conduction disturbance and immediate post-TAVI electrocardiogram. Timing of temporary pacemaker (TPM) removal and hospital discharge were compared with those of the expert panel recommendations to evaluate the associated risk of TPM reinsertion and permanent pacemaker (PPM) implantation.

Results

In most group 1 patients (no electrocardiogram changes without pre-existing right bundle branch block), the timing of TPM removal and discharge were concordant with those of the expert panel recommendations, with low TPM reinsertion (0.8%) and postdischarge PPM (0.8%) rates. In the majority of group 5 patients (procedural high-degree/complete atrioventricular block), TPM was maintained, followed by PPM implantation, compatible with the expert panel recommendations. In contrast, in groups 2-4 (pre-existing/new conduction disturbances), earlier TPM removal than recommended by the expert panel (mostly, immediately after procedure) was feasible in 97.5%-100% of patients, with a low TPM reinsertion rate (0.0%-1.8%); earlier discharge was also feasible in 50.0%-65.5%, with a low 30-day postdischarge PPM rate (0.0%-2.8%) and no 30-day death.

Conclusions

Early TPM removal and discharge after TAVI appear safe and feasible in the majority of cases. These data may provide a framework for an early, streamlined hospital discharge plan for TAVI recipients, optimizing both cost savings and patient safety.

Feasibility and Safety of Same-Day Discharge Following Transfemoral Transcatheter Aortic Valve Replacement

OBJECTIVES

This study evaluated the feasibility and safety of same-day discharge (SDD) following transfemoral transcatheter aortic valve replacement (TF-TAVR) compared with next-day discharge (NDD).

BACKGROUND

Reducing hospital length of stay is an important goal for patients and hospitals. Cleveland Clinic implemented a post-TAVR SDD pathway beginning in March 2020.

METHODS

The study retrospectively analyzed patients who underwent "minimalist" outpatient TF-TAVR in 2019 to 2020. SDD was applied to patients who met the predefined criteria. Outcomes included in-hospital and 30-day events and were compared between SDD and NDD (during and prior to availability of the SDD pathway).

RESULTS

In 2020, SDD and NDD accounted for 22.1% (n = 114 of 516) and 63.8% (n = 329 of 516) of outpatient TF-TAVR, respectively. SDD patients in 2020, compared with NDD patients in 2019 (n = 481), were younger, were more often male, and had a lower surgical risk. There were no significant differences in in-hospital events and 30-day readmissions (cardiovascular readmission: 3.5% vs 6.2%; P = 0.37; noncardiovascular readmission: 2.6% vs 4.0%; P = 0.78), and there were no deaths after SDD. These outcomes remained consistent after propensity score matching. Only 1 (0.9%) patient required pacemaker implantation after SDD (post-TAVR day 25). As expected based on SDD criteria, multivariable logistic regression analysis identified procedure end-time as the strongest predictor of SDD (adjusted OR: 7.74; 95% CI: 4.39-13.63), while male sex and baseline hemoglobin level were also associated with SDD.

CONCLUSIONS

SDD after TF-TAVR was feasible in this early experience without impairing post-discharge safety. Our SDD pathway may serve as a useful strategy to improve bed utilization and reduce hospital stay for TAVR recipients.

Intracaval Leiomyoma with Intracardiac Extension

The aim of the study is to provide a guide on how to achieve a complete resection of an intravascular leiomyoma. A 48-year-old female was referred to our institution with progressive dyspnea on exertion, lightheadedness, and previous history of total abdominal hysterectomy and bilateral salpingoophorectomy for a uterine leiomyoma echocardiography, CT and MRI of heart and abdomen/pelvis were performed and an intracaval mass with extension into the right heart and pulmonary artery was identified. After multidisciplinary review, a single stage sternotomy-laparotomy procedure on cardiopulmonary bypass (with beating heart, mild hypothermia, and no deep hypothermic circulatory arrest) ensured complete resection of a giant intravenous leiomyoma. Multidisciplinary approach, multimodality imaging, and single stage sternotomy-laparotomy procedure on cardiopulmonary by-pass (with heart beating and mild hypothermia) ensure complete resection of intravenous leiomyoma.

Intracaval Leiomyoma with Intracardiac Extension

The objective of this study was to explain step by step how to achieve a complete resection of an intravascular leiomyoma. A 48-year-old woman was referred to our institution with progressive dyspnea on exertion, lightheadedness, and previous history of total abdominal hysterectomy and bilateral salpingo-oophorectomy for a uterine leiomyoma echocardiography, computed tomography, and magnetic resonance imaging of the heart and abdomen/pelvis were performed and an intracaval mass with extension into the right heart and pulmonary artery was identified. After multidisciplinary review, a single-stage sternotomy–laparotomy procedure on cardiopulmonary bypass (with beating heart, mild hypothermia, and no deep hypothermic circulatory arrest) ensured complete resection of a giant intravenous leiomyoma (IVL). Multidisciplinary approach, multimodality imaging, and single-stage sternotomy–laparotomy procedure on cardiopulmonary bypass (with heart beating and mild hypothermia) ensure complete resection of IVL.

Advanced Circulatory Support and Lung Transplantation in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive fatal disease. Although medical therapies have improved the outlook for these patients, there still exists a cohort of patients with PAH who are refractory to these therapies. Lung transplantation (LT), and in certain cases heart-lung transplantation (HLT), is a therapeutic option for patients with severe PAH who are receiving optimal therapy yet declining. ECMO may serve as a bridge to transplant or recovery in appropriate patients. Although, the mortality within the first 3 months after transplant is higher in PAH recipients than the other indications for LT, and the long-term survival after LT is excellent for this group of individuals. In this review, we discuss the indications for LT in PAH patients, when to refer and list patients for LT, the indications for double lung transplant (DLT) versus HLT for PAH patients, types of advanced circulatory support for severe PAH, and short and long-term outcomes in transplant recipients with PAH.

Cardiac Operations after Transcatheter Aortic Valve Replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is now frequently performed for severe aortic stenosis. Data regarding cardiac operations after TAVR are limited, however. Therefore, we investigated patient characteristics, operative timing and indications, and outcomes of these operations in a single-center experience.

METHODS

From 1/2012-7/2020, 59 patients (median age 70) underwent cardiac operations after TAVR, 38 (64%) of the latter performed outside our center. Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) was calculated at time of prior TAVRs and at applicable index cardiac operations.

RESULTS

From 2012-2018, there were fewer than 10 operations after TAVR, but 18 in 2019. Interval between prior TAVR and cardiac surgery decreased exponentially from 7 to less than 1 year over the experience. In applicable cases (n=19; 32%), median STS-PROM was 5.5% (15^th-85th percentiles, 3.1%-25%); 40 (68%) were complex operations with no calculable STS-PROM. The TAVR valve was explanted in 46 (78%); 5 were isolated surgical AVRs. TAVR valve stenosis/regurgitation (n=34; 58%) was the leading indication, followed by paravalvular leak (14; 24%) and endocarditis (n=10/17%). When the TAVR valve was not explanted, mitral regurgitation was the leading indication for operation. Operative mortality was 5 (8.5%), postoperative stroke 2 (3.4%), and postoperative dialysis 6 (10%).

CONCLUSIONS

Cardiac operations after TAVR are increasing and interval between TAVR and operation decreasing. Most cardiac operations are complex, high-risk reoperations and isolated AVR rare. These findings should be considered when TAVR is selected for low-intermediate risk patients, particularly with multiple cardiac pathologies not addressed by TAVR.

Evolution of Alternative-access Transcatheter Aortic Valve Replacement

BACKGROUND

Transfemoral access is the most common approach for transcatheter aortic valve replacement (TAVR). However, a subset of patients require alternative access. This study describes the evolution and outcomes of alternative-access TAVR at Cleveland Clinic.

METHODS

From January 2006 to January 2019, 2446 patients underwent TAVR, 414 (17%) through alternative access (247 transapical, 95 transaortic, 56 transaxillary, 2 transcarotid, 10 transiliac, 4 transcaval). Patients undergoing alternative-access TAVR had high preoperative risk. Propensity-matched comparisons were targeted at comparing transfemoral versus transaxillary approaches since 2012.

RESULTS

Over time, the favored alternative-access approach shifted from transapical and transaortic to transaxillary. Pacemaker requirement was similar for alternative-access and transfemoral approaches. Compared with transfemoral access, major vascular injuries were higher in the alternative-access group (12 [2.9%] vs 27 [1.3%], P = .02), but minor vascular injuries were lower (13 [3.1%] vs 198 [9.8%], P < .0001). Non-risk-adjusted 5-year survival was lower in the alternative-access group (45% vs 59%). Compared with intrathoracic approaches (transapical and transaortic), transaxillary access was associated with fewer blood transfusions (12 [21%] vs 176 [51%], P < .0001), less prolonged ventilation (1 [1.8%] vs 38 [11%], P = .03), and shorter length of stay (median, 5 vs 7.5 days, P < .0001). Survival and major morbidity were similar in matched comparisons of the transfemoral and transaxillary approaches. No brachial plexus injuries occurred with transaxillary access.

CONCLUSIONS

The transaxillary approach has emerged as our preferred alternative-access strategy for TAVR. It is associated with superior operative outcomes compared with transthoracic approaches, and results are comparable with those of the transfemoral approach.

Trends in Outcomes of Transcatheter and Surgical Aortic Valve Replacement in the United States (2012-2017)

As the use of transcatheter aortic valve implantation (TAVI) expands to varying patient populations, impacting the landscape of surgical aortic valve replacement (SAVR), this study sought to assess volume and performance trends of aortic valve replacement (AVR) in the United States during 2012-2017. The Nationwide Readmissions Database was queried for patients who underwent endovascular/transapical TAVI, isolated SAVR, or complex aortic valve surgery between 2012 and 2017. Temporal trends in annual case volume, admission costs, in-hospital outcomes, and 30-day readmission were evaluated. Of 624,303 patients (median age 72 years) who received AVR, 387,011 (62%) were men. Among these patients, 170,521 (27%) underwent TAVI and 453,782 (73%) underwent SAVR with 299,398 isolated and 154,384 complex aortic valve surgery. TAVI patients were significantly older and higher risk compared with SAVR patients. From 2012 to 2017, the annual number of TAVI increased from 8,295 to 55,168 whereas SAVR volume remained remarkably stable. Patients who underwent AVR demonstrated significant improvements in mortality, stroke, duration of hospitalization, and 30-day readmission. In conclusion, this large contemporary analysis reports the considerable growth of AVR in the United States. It remains unequivocal that the treatment of aortic stenosis is improving overall with reduced mortality following AVR, highlighting the effectiveness of various process improvements such as newer valves, enhanced patient selection, and the interdisciplinary Heart Team approach.

The Effect of Blood Transfusion in Lung Donors on Recipient Survival

BACKGROUND

Blood transfusion can have detrimental effects on the pulmonary system, leading to lung injury and respiratory decompensation with subsequent increased morbidity and mortality in surgical and critically ill patients. How much of this effect is carried from a lung donor to transplant recipient is not fully understood, raising questions regarding transplant suitability of lungs from transfused donors.

METHODS

United Network for Organ Sharing data were reviewed. Lung transplants from adult donors and known donor transfusion status were included; multiorgan transplants and retransplants were excluded. Recipient mortality was evaluated based on donor and recipient characteristics using a Kaplan-Meier survival estimate, Cox proportional hazards, and logistic regression models. We further assessed whether recipient mortality risk modified the donor transfusion effect.

RESULTS

From March 1996 to June 2017, 20,294 transplants were identified. Outcome analysis based on transfusion status showed nonsignificant difference in 1-year mortality (P = .214). Ninety-day recipient mortality was significantly higher with transfusion of >10 units (U) vs 1-10 U or no transfusion (8.5%, 6.1%, and 6.0%, respectively, P = .005). Multivariable analysis showed increased 90-day mortality with transfusion of >10 U compared to no transfusion (odds ratio 1.62, P < .001), whereas 1-10 U showed no difference (odds ratio 1.07, P = .390). When stratified by recipient transplant risk, transfusion of >10 U was associated with increased mortality even with the lowest-risk recipients, while transfusion of 1-10 U showed no mortality increase even in the highest-risk recipients.

CONCLUSIONS

Donor transfusion of >10 U of blood was associated with increased 90-day recipient mortality even in low-risk transplants. This risk should be considered when evaluating donor lungs.

Cellular Ex Vivo Lung Perfusion Beyond 1 Hour May Improve Marginal Donor Lung Assessment

BACKGROUND

Ex vivo lung perfusion (EVLP) permits extended evaluation of donor lungs for transplant. However, the optimal EVLP duration of Lund protocol is unclear. Using human lungs rejected for clinical transplant, we sought to compare the results of 1 versus 2 h of EVLP using the Lund protocol.

METHODS

Twenty-five pairs of human lungs rejected for clinical transplant were perfused with the Lund EVLP protocol. Blood gas analysis, lung compliance, bronchoscopy assessment, and perfusate cytokine analysis were performed at both 1 and 2 h. Recruitment was performed at both time points. Donor lung transplant suitability was determined at both time points.

RESULTS

All cases were divided into four groups based on transplant suitability assessment at 1 h and 2 h of EVLP. In group A (n = 10), lungs were judged suitable for transplant at both 1 and 2 h of EVLP. In group B (n = 6), lungs were suitable at 1 h but nonsuitable at 2 h. In group C (n = 2), lungs were nonsuitable at 1 h but suitable at 2 h. Finally, in group D (n = 7), lungs were nonsuitable for transplant at both time points. In both groups B and C (n = 8), the transplant suitability assessment changed between 1 and 2 h of EVLP.

CONCLUSIONS

In human lungs rejected for transplant, transplant suitability differed at 1 versus 2 h of EVLP in 32% of lungs studied. Evaluation of lungs with Lund protocol EVLP beyond 1 h may improve donor organ assessment.

Lung transplant with bronchial arterial revascularization: review of surgical technique and clinical outcomes

Lung transplantation (LTx) is routinely performed with sacrifice of the bronchial arterial circulation. We review bronchial artery anatomy and surgical technique for LTx with direct bronchial arterial revascularization (BAR). We also update the published clinical experience, including from our center, of LTx with BAR. Published series of LTx with BAR are from single centers, and all cite high technical success rates and good short-term outcomes. Technically, double LTx (DLTx) with BAR is almost always possible if a deliberate review of bronchial artery anatomy is performed. For single LTx (SLTx), BAR is feasible in about 50% of cases. The combined Copenhagen and Cleveland Clinic experience (with BAR procedures performed or supervised by Dr. Gosta B. Pettersson) includes 131 LTx with BAR with a technical success rate >95%. Procedural success is uniformly associated with normal airway healing. Five-year survival in LTx with BAR is superior to the 5-year survival of LTx patients in the ISHLT registry. LTx with BAR is feasible and safe, and technical success ensures normal airway healing. The experience with BAR at experienced centers suggests possible long-term survival benefit. A multicenter study is needed to define the role of BAR in LTx.

Dual antiplatelet therapy versus aspirin monotherapy in diabetics with stable ischemic heart disease undergoing coronary artery bypass grafting

Background

Dual antiplatelet therapy (DAPT) in patients presenting with acute coronary syndrome (ACS) undergoing CABG is recommended to prevent recurrent ischemic events. The benefit of DAPT post-CABG in patients with stable ischemic heart disease (SIHD) is unknown. The aim of this study was to evaluate the utilization rate of DAPT and associated outcomes in patients with SIHD undergoing CABG via a secondary analysis of Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial data.

Methods

In a post-hoc, nonrandomized analysis from the BARI 2D trial, we compared patients receiving DAPT and aspirin monotherapy within 90 days post-randomization. The primary outcome was the risk adjusted 5-year composite of all-cause mortality, nonfatal myocardial infarction (MI), or stroke. We analyzed patients assigned to prompt CABG treatment arm including both the insulin therapy assignments.

Results

Of 378 patients, within 90 days post-randomization, 59 (16%) patients received DAPT and 319 (84%) patients received aspirin alone. Cox proportional hazard analysis demonstrated that there was no significant difference in the 5-year composite event of death, MI, and stroke between DAPT and monotherapy cohorts [13 (22.0%) vs. 61 (19.1%); adjusted hazard ratio (HR): 1.06; 95% confidence interval (CI): 0.56 to 2.00; P=0.86]. There also was no significant difference at 1 year in the composite event [6 (10.2%) vs. 30 (9.4%); HR: 1.13; 95% CI: 0.46 to 2.79; P=0.79].

Conclusions

The use of DAPT in patients with diabetes post-CABG in this cohort was low. Compared with aspirin monotherapy, no associated differences were observed in cardiovascular outcomes. Larger prospective studies are needed to further elucidate this observation.

Isolated Tricuspid Valvectomy: A Series of cases with Intravenous Drug Abuse Associated Tricuspid Valve Endocarditis

INTRODUCTION

 Surgical management for tricuspid valve (TV) endocarditis is usually TV repair or replacement. When repair is not feasible, and concerns for patient recidivism preclude TV replacement, tricuspid valvectomy without replacement is an option to alleviate symptoms and allow time for addiction management.

METHODS

 We reviewed our institution's experience with isolated tricuspid valvectomy for cases of intravenous drug use (IVDU)-associated endocarditis (n = 7) from 2009 to 2017.

RESULTS

 The decision for tricuspid valvectomy was based on each patient's comorbid condition and realization of active IVDU. This intervention resulted in 100% perioperative and mid-term survival with a mean follow-up of 25.4 months. One patient required a valve replacement in the long term only after appropriate substance abuse management was completed.

CONCLUSION

 Cardiac surgeons increasingly encounter patients with active endocarditis who suffer from IVDU addiction. Drug addiction increases the risk for recurrent endocarditis and requires an effective management plan. Multidisciplinary endocarditis care teams may play a pivotal role in improving outcomes by better addressing addiction treatment.

ISHLT Consensus Statement on adult and pediatric airway complications after lung transplantation: Definitions, grading system, and therapeutics

Airway complications remain a major cause of morbidity and mortality after cardiothoracic transplantation. The reported incidence of airway ischemic complications varies widely, contributed to by the lack of a universally accepted grading system and standardized definitions. Furthermore, the majority of the existing classification systems fail to integrate the wide range of possible bronchial complications that may develop after lung transplant. Hence, a Working Group was created by the International Society for Heart and Lung Transplantation with the aim of elaborating a universal definition of adult and pediatric airway complications and grading system. One such area of focus is to understand the problem in the context of a more standardized consensus of classifying airway ischemia. This consensus definition will have major clinical, therapeutics, and research implications.

Heart transplant outcomes in recipients of Centers for Disease Control (CDC) high risk donors

BACKGROUND

A lack of donor hearts remains a major limitation of heart transplantation. Hearts from Centers for Disease Control (CDC) high-risk donors can be utilized with specific recipient consent. However, outcomes of heart transplantation with CDC high-risk donors are not well known. We sought to define outcomes, including posttransplant hepatitis and human immunodeficiency virus (HIV) status, in recipients of CDC high-risk donor hearts at our institution.

METHODS

All heart transplant recipients from August 2010 to December 2014 (n = 74) were reviewed. Comparison of 1) CDC high-risk donor (HRD) versus 2) standard-risk donor (SRD) groups were performed using chi-squared tests for nominal data and Wilcoxon two-sample tests for continuous variables. Survival was estimated with Kaplan-Meier curves.

RESULTS

Of 74 heart transplant recipients reviewed, 66 (89%) received a SRD heart and eight (11%) received a CDC HRD heart. We found no significant differences in recipient age, sex, waiting list 1A status, pretransplant left ventricular assist device (LVAD) support, cytomegalovirus (CMV) status, and graft ischemia times (p = NS) between the HRD and SRD groups. All of the eight HRD were seronegative at the time of transplant. Postoperatively, there was no significant difference in rejection rates at six and 12 months posttransplant. Importantly, no HRD recipients acquired hepatitis or HIV. Survival in HRD versus SRD recipients was not significantly different by Kaplan-Meier analysis (log rank p = 0.644) at five years posttransplant.

CONCLUSION

Heart transplants that were seronegative at the time of transplant had similar posttransplant graft function, rejection rates, and five-year posttransplant survival versus recipients of SRD hearts. At our institution, no cases of hepatitis or HIV occurred in HRD recipients in early follow-up.

Interferon-γ-mediated allograft rejection exacerbates cardiovascular disease of hyperlipidemic murine transplant recipients

RATIONALE

Transplantation, the most effective therapy for end-stage organ failure, is markedly limited by early-onset cardiovascular disease (CVD) and premature death of the host. The mechanistic basis of this increased CVD is not fully explained by known risk factors.

OBJECTIVE

To investigate the role of alloimmune responses in promoting CVD of organ transplant recipients.

METHODS AND RESULTS

We established an animal model of graft-exacerbated host CVD by combining murine models of atherosclerosis (apolipoprotein E-deficient recipients on standard diet) and of intra-abdominal graft rejection (heterotopic cardiac transplantation without immunosuppression). CVD was absent in normolipidemic hosts receiving allogeneic grafts and varied in severity among hyperlipidemic grafted hosts according to recipient-donor genetic disparities, most strikingly across an isolated major histocompatibility complex class II antigen barrier. Host disease manifested as increased atherosclerosis of the aorta that also involved the native coronary arteries and new findings of decreased cardiac contractility, ventricular dilatation, and diminished aortic compliance. Exacerbated CVD was accompanied by greater levels of circulating cytokines, especially interferon-γ and other Th1-type cytokines, and showed both systemic and intralesional activation of leukocytes, particularly T-helper cells. Serological neutralization of interferon-γ after allotransplantation prevented graft-related atherosclerosis, cardiomyopathy, and aortic stiffening in the host.

CONCLUSIONS

Our study reveals that sustained activation of the immune system because of chronic allorecognition exacerbates the atherogenic diathesis of hyperlipidemia and results in de novo cardiovascular dysfunction in organ transplant recipients.

Heart transplantation

Over the past 40 years, heart transplantation has become a routine treatment for end-stage heart failure. Over 3000 heart transplants are performed annually. Despite improvements in short-term outcomes, long-term survival remains limited. Current efforts remain directed at alleviating the shortage of donor organs, developing effective treatments for chronic rejection, and improving mechanical circulatory support for heart failure.

Lung transplantation: past, present, and future

Lung transplantation (LTx) is an established therapy for end-stage lung disease (ESLD). Survival after LTx is limited by infection and rejection, particularly bronchiolitis obliterans syndrome (BOS). New techniques with the potential to increase donor lung supply and prevent rejection continue to evolve. These developments hold promise for improved outcomes for a greater number of patients.

mRNA differential display identification of vascular smooth muscle early response genes regulated by PDGF

The modulation of vascular smooth muscle cells (VSMCs) from the quiescent phenotype to the proliferative and migratory phenotype is a critical event in the pathogenesis of atherosclerosis. To-date several growth factors, including platelet-derived growth factor, PDGF, have been shown to induce VSMC proliferation and migration. To further understand the mechanism of PDGF-induced VSMC activation, quiescent human coronary artery SMC were treated with PDGF, and the genes that displayed transcriptional changes within 3 and 8 h were identified using differential display RT-PCR, real-time PCR, nucleotide sequencing and bioinformatics. Eleven genes that were highly upregulated or down-regulated at 3 and/or 8 h by PDGF, designated growth-factor regulated VSMC genes (GRSG1-11), were analyzed. GRSG5 and GRSG9-1 were identified as cortactin and cytochrome c oxidase subunit II, respectively. The remaining nine GRSGs were novel. GRSG3, 4, 5 and 9-2 showed wide tissue distribution whereas GRSG10-1, 10-2, and 11 were tissue specific. Cortactin was localized by immunohistochemical staining to the neointima and fibrous cap of human coronary artery atherosclerotic plaques. Domain analysis of open reading frames suggest that the novel GRSGs may participate in signaling, metabolic, translational or migrational processes during PDGF-induced VSMC activation.

Genomic DNA functions as a universal external standard in quantitative real-time PCR

Real-time quantitative PCR (qPCR) is a powerful tool for quantifying specific DNA target sequences. Although determination of relative quantity is widely accepted as a reliable means of measuring differences between samples, there are advantages to being able to determine the absolute copy numbers of a given target. One approach to absolute quantification relies on construction of an accurate standard curve using appropriate external standards of known concentration. We have validated the use of tissue genomic DNA as a universal external standard to facilitate quantification of any target sequence contained in the genome of a given species, addressing several key technical issues regarding its use. This approach was applied to validate mRNA expression of gene candidates identified from microarray data and to determine gene copies in transgenic mice. A simple method that can assist achieving absolute quantification of gene expression would broadly enhance the uses of real-time qPCR and in particular, augment the evaluation of global gene expression studies.

CD8 Lymphocytes are Sufficient for the Development of Chronic Rejection

BACKGROUND

The role of CD8 lymphocytes, in chronic rejection or cardiac allograft vasculopathy (CAV), is incompletely understood. The purposes of this study were to determine whether CD8 lymphocytes, in the absence of CD4 lymphocytes, are capable of causing the intimal lesions of CAV; and if so, to define the effector mechanism(s) of CD8 lymphocytes.

METHODS

We modified a previously characterized major histocompatibility complex class II mismatched murine model of CAV. Wild-type CD8 lymphocytes were transferred to nude mice followed by heterotopic heart transplantation. Recipient mice were then treated with a CD40 activating antibody, which is known to provide help for CD8 lymphocyte activation, in the absence of CD4 lymphocytes. Donor hearts were harvested on day 40 posttransplantation and analyzed for cellular infiltrates and intimal thickening. In separate experiments, isolated perforin -/-, Fas ligand (FasL) -/-, and interferon (IFN)-gamma -/- CD8 lymphocytes were transferred to nude mice followed by identical experimented protocol.

RESULTS

With adaptive transfer of wild-type CD8 lymphocytes, the donor hearts were infiltrated with activated CD8 lymphocytes and displayed significant intimal lesions. Adoptive transfer of perforin -/- and FasL -/- CD8 lymphocytes to nude mice resulted in similar patterns of CD8 lymphocyte infiltration and similar severity of intimal lesions. The donor hearts from IFN-gamma -/- CD8 lymphocyte reconstituted recipients displayed minimal intimal lesions, although CD8 lymphocytes were present in the allografts.

CONCLUSIONS

Unprimed CD8 lymphocytes in the absence of CD4 lymphocytes can cause intimal lesions of CAV. CD8 lymphocytes production of IFN-gamma, but not the perforin or the FasL-mediated cytotoxicity, is the critical step in the development of intimal lesions.

Chemokine Monokine Induced by IFN-γ/CXC Chemokine Ligand 9 Stimulates T Lymphocyte Proliferation and Effector Cytokine Production

Monokine induced by IFN-gamma (MIG; CXC chemokine ligand (CXCL)9) is important in T lymphocyte recruitment in organ transplantation. However, it is not known whether this chemokine, in addition to its chemotactic properties, exerts any effect on T lymphocyte effector functions. For in vivo studies, we used a previously characterized murine model of chronic rejection. The recipient mice were treated with anti-MIG/CXCL9 Ab; graft-infiltrating cells were analyzed for IFN-gamma production. For in vitro studies, exogenous CXCR3 ligands were added to CD4 lymphocytes in MLRs, and the proliferative responses were measured. Separate experiments quantitated the number of IFN-gamma-producing cells in MLRs by ELISPOT. Neutralization of MIG/CXCL9, in the in vivo model, resulted in significant reduction in the percentage of IFN-gamma-producing graft-infiltrating T lymphocytes. In vitro experiments demonstrated that 1) exogenous MIG/CXCL9 stimulated CD4 lymphocyte proliferation in a MHC class II-mismatched MLR, 2) MIG/CXCL9 also increased the number of IFN-gamma-producing CD4 lymphocytes in ELISPOT, 3) neutralization of MIG/CXCL9 in MLR reduced T lymphocyte proliferation, 4) IFN-gamma-inducible protein 10/CXCL10 and IFN-inducible T cell alpha chemoattractant/CXCL11 had similar effects on T lymphocyte proliferation, 5) MIG/CXCL9 stimulated T lymphocyte proliferation in MHC class I- and total MHC-mismatched MLRs, 6) neutralization of CXCR3 reduced MIG/CXCL9-induced T lymphocyte proliferation and the number of IFN-gamma-positive spots on ELISPOT, and 7) the proliferative effects of MIG/CXCL9 were mediated via an IL-2-independent pathway and were controlled by IFN-gamma. This study demonstrates that MIG/CXCL9 stimulates T lymphocyte proliferation and effector cytokine production, in addition to its chemotactic effects. This novel observation expands our current understanding of MIG/CXCL9 biology beyond that of mediating T cell trafficking.

Combined blockade of the chemokine receptors CCR1 and CCR5 attenuates chronic rejection

BACKGROUND

Chemokine-chemokine receptor interaction and the subsequent recruitment of T-lymphocytes to the graft are early events in the development of chronic rejection of transplanted hearts or cardiac allograft vasculopathy (CAV). In this study, we sought to determine whether blockade of chemokine receptors CCR1 and CCR5 with Met-RANTES affects the development of CAV in a murine model.

METHODS AND RESULTS

B6.CH-2(bm12) strain donor hearts were transplanted heterotopically into wild-type C57BL/6 mice (myosin heavy chain II mismatch). Recipients were treated daily with either Met-RANTES or vehicle starting on postoperative day 4 and were euthanized on postoperative days 24 and 56. We found that Met-RANTES significantly reduced intimal thickening in this model of chronic rejection and that Met-RANTES markedly decreased the infiltration of CD4 and CD8 T lymphocytes and MOMA-2+ monocytes/macrophages into transplanted hearts. Met-RANTES also suppressed the ex vivo and in vitro proliferative responses of recipient splenocytes to donor antigens. Finally, Met-RANTES treatment was associated with a marked reduction in RANTES/CCL5 and monocyte chemoattractant protein-1 gene transcript levels in the donor hearts.

CONCLUSIONS

Antagonism of the chemokine receptors CCR1 and CCR5 with Met-RANTES attenuates CAV development in vivo by reducing mononuclear cell recruitment to the transplanted heart, proliferative responses to donor antigens, and intragraft RANTES/CCL5 and monocyte chemoattractant protein-1 gene transcript levels. These findings suggest that chemokine receptors CCR1 and CCR5 play significant roles in the development of chronic rejection and may serve as potential therapeutic targets.

The role of MIG/CXCL9 in cardiac allograft vasculopathy

T lymphocytes play a critical role in chronic rejection of transplanted hearts, or cardiac allograft vasculopathy (CAV). However, the molecular mediators of T lymphocyte recruitment in CAV are incompletely defined. We hypothesized that the chemokine, monokine induced by interferon-gamma (MIG/CXCL9), which induces T lymphocyte migration in vitro, participates in T lymphocyte recruitment in CAV. In a previously characterized MHC II-mismatched murine model of CAV, intragraft MIG/CXCL9 gene transcript and protein levels increased on days 7, 14, and 24 days after transplantation, paralleling T lymphocyte recruitment and preceding intimal thickening. Antibody neutralization of MIG/CXCL9 significantly reduced CD4(+) T lymphocyte infiltration and intimal thickening in this model. MIG/CXCL9 was produced by graft-infiltrating MOMA-2+ macrophages in early and late stages of CAV. And, although T lymphocytes did not produce MIG/CXCL9, recipient CD4(+) T lymphocytes were required for sustained intragraft MIG/CXCL9 production and CAV development. These findings demonstrate that 1) MIG/CXCL9 plays an important role in CD4(+) T lymphocyte recruitment and development of CAV, 2) MOMA-2+ macrophages are the predominant recipient-derived source of MIG/CXCL9, and 3) recipient CD4 lymphocytes are necessary for sustained MIG/CXCL9 production and CAV development in this model. Neutralization of the chemokine MIG/CXCL9 may have therapeutic potential for the treatment of chronic rejection after heart transplantation.

Rantes production during development of cardiac allograft vasculopathy

BACKGROUND

RANTES (regulated on activation, normal T cell expressed and secreted) production has been shown to correlate with mononuclear cell recruitment and precede intimal thickening in cardiac allograft vasculopathy (CAV). However, the cells that produce RANTES in CAV are undefined. Therefore, in an MHC II-mismatched murine model of CAV, we sought to (1) define the cellular sources of RANTES and (2) determine the role of CD4+ lymphocytes in RANTES production during CAV development.

METHODS

B6.CH-2bm12 strain donor hearts were transplanted heterotopically into wild-type (WT) or CD4 knockout (CD4KO) C57BL/6 mice (MHC II mismatch). No immunosuppression was used. Recipients were sacrificed at 7, 14, and 24 days. Intragraft RANTES gene expression and protein levels were determined with ribonuclease protection assay and ELISA, respectively. At days 7 and 24, RANTES production by graft-infiltrating cells was defined with intracellular RANTES staining and multicolor FACS analysis. Intimal thickening was quantitated morphometrically. In murine hearts and in six explanted human hearts with advanced CAV, RANTES was also localized immunohistochemically.

RESULTS

NK, NKT, and gammadelta+ cells, in addition to CD4+, CD8+ lymphocytes, and CD11b+ macrophages, produced RANTES in early and late stages of CAV. RANTES-producing NK, NKT, and gammadelta+ cells tripled in number during CAV development; by day 24, NK and gammadelta+ cells each outnumbered CD4+ lymphocytes and CD11b+ macrophages. The presence of CD4+ lymphocytes was required for sustained RANTES production in allografts, which correlated with mononuclear cell recruitment and preceded intimal thickening. In murine and explanted human hearts with advanced CAV, RANTES immunolocalized with graft-infiltrating mononuclear cells and vessel wall cells.

CONCLUSIONS

We present evidence that other cell types in addition to CD4+, CD8+ T lymphocytes, and CD11b+ macrophages contribute significantly to RANTES production in CAV. In this MHC II-mismatched murine model of CAV, sustained RANTES production requires CD4+ lymphocytes, correlates with mononuclear cell recruitment, and precedes intimal thickening. In experimental and human CAV, vessel wall cells may also produce RANTES. Interventions aimed at inhibiting RANTES production in CAV may need to target several types of cells, and neutralization of RANTES bioactivity may reduce mononuclear cell recruitment and CAV development.