Transcatheter aortic valve implantation without contrast media technique in chronic kidney disease population – pilot study

Background/Introduction

Acute Kidney Injury (AKI) is frequently observed after Transcatheter aortic valve implantation (TAVI), with rates ranging from 3% to 50%. In the Brazilian TAVI Registry, the incidence of AKI following TAVI was 18%, with 4.5% requiring dialysis. Its occurrence is associated with an increase in 3-fold all-cause and cardiac death. Since AKI is related to the volume of contrast media, avoiding contrast during TAVI procedure is advisable, especially in chronic kidney disease (CKD) patients.

Purpose

The aims of the proposed study are to: (1) evaluate the feasibility and safety of a zero-contrast technique for CKD patients undergoing TAVI and (2) define the role of each of the non-contrast imaging modalities in the preoperative assessment for TAVI and (3) evaluate the incidence of AKI post-TAVI in this population.

Methods

Patients with severe symptomatic aortic stenosis (AS) and CKD stage ≥3a where evaluated for TAVI with four preoperative exams: transesophageal echocardiogram (TEE), cardiac magnetic resonance, contrast and noncontrast computed tomography (MDCT) and aortoiliac co2 angiography. After safety measures of transfemoral (TF) viability and aortic valve favorable anatomy, patients were submitted to TF-TAVI with self-expandable Evolut R/Pro. The contrast MDCT was blinded to the operators and it is checked before the procedure, at a safety checkpoint, to exclude high-risk conditions not detected by non-contrast methods. During the procedure, another safety checkpoint was accomplished. Clinical and echocardiographic outcomes were assessed at 30 days.

Results

Between december 2020 to december 2021, a total of 25 patients underwent TF TAVI with zero-contrast technique. Mean age of 79.9±6.1 years, 52% male, 18 patients (72%) NYHA functional class III or IV, mean STS-PROM 3.0±1.5%, 12% had severe systolic dysfunction (left ventricle ejection fraction <35%) and mean creatinine clearance of 49.1±7 mL/min. Self-expandable Evolut R was implanted in 80% of patients and Evolut Pro in 20% of them, the most frequent THV size was 29 mm (52%) and the mean implant depth was 6 mm in fluoroscopy and 4.5 mm in TEE. The mean procedural time was 138±56 minutes, with a median radiation dose of 6.6 mGy/cm2 [IQR, 2–6 mGy]. Definitive pacemaker was implanted in 17% of patients and AKI was seen in 6 patients (24%), with stage I (20%), stage II (4%) and no case needed hemodialysis. At 30 days, 84% were at functional class I, there was no death, one embolization requiring a second valve and the rate of device success (VARC-2) was 92%.

Conclusion

The proposed pilot study for transfemoral TAVI in CKD population with zero contrast technique was safe, with promising results and similar rates of success and complication, compared with the conventional TAVI approach.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): MedtronicAngiodroid

P6483Predictors of contractile reserve on dobutamine stress echocardiography in patients with classical low-flow, low-gradient aortic stenosis

Background

There is a lack of information on factors that influence contractile reserve (CR) on dobutamine stress echocardiography (DSE) in patients with classical low-flow, low-gradient aortic stenosis (LFLG-AS).

Purpose

This study sought to evaluate the predictors of CR in patients with LFLG-AS.

Methods

Prospective study including 43 consecutive LFLG-AS patients (aortic valve area [AVA] ≤1.0 cm2, mean transaortic gradient <40 mmHg, left ventricular ejection fraction [LVEF] <50%) with true severe aortic stenosis. All patients underwent dobutamine stress echocardiography and T1-mapping cardiac magnetic resonance (CMR). CR was defined as an increase ≥20% in the left ventricular stroke volume at peak stress. Patients with pseudo-severe aortic stenosis were excluded.

Results

All of the patients in the study had degenerative aortic stenosis, with a median age of 67 [60–74] years, most of them being male (83.7%). A high prevalence of comorbidities was found, highlighted by diabetes (42%), hypertension (70%), atrial fibrillation (25%) and coronary artery disease (38%). Mean transaortic gradient was 25 [20–33] mmHg, AVA was 0.88 [0.68–0.95] cm2, LVEF was 35 [28–43]% and 32.6% had moderate/severe functional mitral regurgitation. CMR myocardium extracellular volume fraction (ECV) was 28.8 [26.3–33.0] %, indexed ECV was 35.4 [25.0–41.2] ml/m2, 32.6% had positive transmural delayed-enhancement images and 25.6% had positive mesocardial delayed-enhancement images. On DSE, 30 patients (69.7%) had CR and 13 patients (30.3%) had no CR. Global longitudinal strain was 10 [7–12] %, Δ indexed flow rate was 25 [3–38] ml/m2.seg and Δ mean gradient was 10 [3–16] mmHg. By multivariate analysis, moderate/severe functional mitral regurgitation (HR 0.122, 95% CI 0.020–0.759, p=0.024) and AVA (HR 0.606, 95% CI 0.396–0.925, p=0.020 [for each increase of 0.05 cm2]) were the only factors associated with CR. ECV, indexed ECV and positive transmural or mesocardial delayed-enhancement images were not associated with CR in the univariate analysis.

Conclusions

In our study, the absence of moderate/severe functional mitral regurgitation and AVA were predictors of CR on DSE in patients with LFLG-AS. As AVA was smaller in patients with CR, our finding contradicts the hypothesis that more severe aortic stenosis could also contribute to the lack of CR. Other possible factors that are surrogate of myocardium fibrosis, as ECV, indexed ECV and positive delayed-enhancement images, were not associated with the absence of CR.

Acknowledgement/Funding

FAPESP

Immunohistochemical quantification of inflammatory cells in endomyocardial biopsy fragments after heart transplantation: a new potential method to improve the diagnosis of rejection after heart transplantation

Inconsistencies in cardiac rejection grading systems corroborate the concept that the evaluation of inflammatory intensity and myocyte damage seems to be subjective. We studied in 36 patients the potential role of the immunohistochemical (IHC) counting of inflammatory cells in endomyocardial biopsy (EMB) as an objective tool, testing the hypothesis of correlation between the International Society for Heart and Lung Transplantation 2004 rejection and IHC counting of inflammatory cells. We observed a progressive increment in CD68+ cells/mm(2) (P = .000) and CD3+ cells/mm(2) (P = .000) with higher rejection grade. A strong correlation between the grade of cellular rejection and both CD68+ cells/mm(2) and CD3+ cells/mm(2) was obtained (P = .000). One patient with CD3+ and CD68+ cells/mm(2) above the upper limit of the 95% confidence interval for cells/mm(2) found in rejection grade 1R evolved to rejection grade 2R without treatment. In patients with 2R that did not respond to treatment the values of CD68+ or CD3+ cells were higher than the overall median values for rejection grade 2R. For diagnosis of rejection needing treatment, the CD68+ and CD3+ cells/mm(2) areas under the receiver operating characteristic curves were 0.956 and 0.934, respectively. IHC counting of mononuclear inflammatory infiltrate in EMB seems to have additive potential role in evaluation of EMB for the diagnosis and prognosis of rejection episodes.

Rheumatic fever: how S. pyogenes-primed peripheral T cells trigger heart valve lesions

The pathogenesis of rheumatic fever (RF) is related to autoimmune humoral and cellular responses against human tissues triggered by Streptococcus pyogenes. CD4(+) T cells are the ultimate effectors of chronic heart lesions in rheumatic heart disease (RHD). Heart-infiltrating CD4(+) T cell clones are able to recognize heart tissue and streptococcal antigens by molecular mimicry. The streptococcal M5(81-103) region, an immunodominant region, was recognized by both intralesional and peripheral T cell clones (62% and 38%, respectively). Peripheral T lymphocytes from Brazilian patients with severe RHD preferentially recognized the M5(81-96) peptide, in the context of HLA-DR7(+) and DR53(+) molecules. HLA-DR7 seems to be related to the development of multiple valvular lesions in RHD patients from different countries. In addition, the fact that peripheral and intralesional T cells recognized the M5(81-103) region points to this region as one of the streptococcal triggers of autoimmune reactions in RHD. T cell repertoire analysis from peripheral and intralesional T cell lines derived from RHD patients showed several oligoclonal expansions of BV families. Major expansions were found in the heart lesions, suggesting that such T cell populations preferentially migrate from the periphery to the heart. Some cross-reactive intralesional T cell clones displayed the same T cell receptor (TCR) BVBJ and CDR3 sequences, showing a degenerate pattern of antigen recognition. Heart tissue-infiltrating cells from myocardium and valvular tissue produced TNF-alpha, IFN-gamma, IL-10, and IL-4, whereas few cells from valvular tissue produced IL-4, showing that the lack of regulation in the valves could be responsible for the permanent and progressive valvular lesions.

Repeated echocardiographic examinations of patients with suspected infective endocarditis

OBJECTIVE

To study the diagnostic contribution of repeated transthoracic (TTE) and transoesophageal echocardiography (TOE) among patients with suspected infective endocarditis.

METHODS

262 patients with 266 episodes of suspected infective endocarditis were referred for TTE and TOE over three years in a 423 bed university cardiology hospital. Patients were a mean (SD) of 47.6 (17.9) years old. 139 (52.3%) episodes occurred in men and 127 (47.7%) in women. The diagnostic information obtained from repeated TTE and TOE examinations was evaluated relative to the diagnosis of endocarditis.

RESULTS

TTE examinations were repeated in 192 (72.2%) and TOE examinations were repeated in 49 (18.4%) of 266 episodes. A mean of 2.4 TTE and 1.2 TOE examinations were performed for each episode of suspected endocarditis. The second and third TTEs added diagnostic information in 34 (26.7%) and the second and third TOEs added diagnostic information in 25 (19.7%) of 127 episodes with definite endocarditis. After the third TTE or TOE no additional diagnostic information was obtained.

CONCLUSIONS

The diagnostic contribution of repeated TTE or TOE for the diagnosis of endocarditis decreased as the number of repetitions increased. In this setting, the data do not substantiate more than three TTE or TOE examinations as an efficient strategy to increase the diagnostic yield for all but selected patients with suspected endocarditis.