INTRODUCTION

The most prevalent valvular disease in developed countries frequently involves the aortic valve, and aortic stenosis (AS) is the most common condition. (1) In recent decades, due to increased life expectancy, the treatment of this condition has become increasingly important. The range of therapeutic options has evolved, and all alternatives aim to reduce surgical risk in the general population, particularly among elderly patients. Beginning with aortic valve replacement (AVR) by median sternotomy, progress was made with the development of new transcatheter aortic valve implantation (TAVI) techniques. This treatment was originally developed to provide a less invasive option for high-risk patients and is now not only the gold standard of care for that group but has also been extended to include low- and intermediate-risk patients. (2-4)

The development of rapid deployment valves (RDV) represents an innovation. This device combines the safety and long-term durability provided by the Perimount Carpentier-Edwards valve platform, with an anchoring mechanism derived from transcatheter techniques, reducing pump and aortic clamping times while ensuring a favorable hemodynamic profile. (5-10) The use of these devices facilitates the development of minimally invasive techniques (mini thoracotomy, mini sternotomy, or transaxillary approaches) which, due to their low surgical invasiveness, reduce blood loss, mechanical ventilation time, and the intensive care unit and hospital length of stay, thereby promoting a faster recovery. (11-14) In 2018, our center launched a program using RDV, and the combination of these valves with minimally invasive surgery yielded results similar to those reported in the literature. (12-15) In this study, we present our initial experience in this field at a high-volume valve surgery center.

OBJECTIVES

The primary objective of this study was to evaluate postoperative mortality at one month and one year following AVR via mini sternotomy, using INTUITY rapid-deployment valves (INTUITY Elite, Edwards Lifesciences, Irvine, CA, USA). As a secondary objective, we analyzed the incidence of intraoperative and postoperative complications, as well as pre- and postoperative transprosthetic valve gradients within the first 30 days after surgery.

METHODS

A single-center, retrospective, observational cohort study was conducted, analyzing the electronic medical records of all patients who underwent AVR in the department of cardiovascular surgery at Hospital Italiano de Buenos Aires between March 2018 and July 2024. Patients between 50 to 85 years of age with severe AS meeting diagnostic criteria established by clinical practice guidelines (1-3) were included in the study. These patients underwent surgery via J- or T-shaped mini sternotomy using the INTUITY RDV (INTUITY Elite, Edwards Lifesciences, Irvine, CA, USA), regardless of surgical risk, for both tricuspid and bicuspid valves. Patients who underwent another type of minimally invasive approach [transaxillary, right anterior thoracotomy (RAT)] or full sternotomy, those who received a prosthesis other than a RDV, or had an indication for another associated surgery, and those with infectious endocarditis were excluded from the study.

The following variables were evaluated: a) Clinical: age, sex, body mass index (BMI), cardiovascular history, chronic obstructive pulmonary disease (COPD), prior dialysis, presence of a bicuspid valve, left ventricular systolic function, usual functional class (NYHA), and STS-PROM score; b) Surgical: type of surgery, incidence of conversion to full sternotomy, valve size, prosthetic explantation and use of conventional valve, cardiopulmonary bypass (CPB) and aortic clamping times, and presence of paravalvular leak assessed by transesophageal echocardiography; c) Perioperative complications: prolonged mechanical ventilation (> 48 hours post-surgery), need for intra-aortic balloon pump (IABP), acute myocardial infarction (AMI), ischemic stroke, blood loss within 24 hours, units of red blood cells transfused, need for reoperation due to bleeding, cardiac arrhythmias, pacemaker (PM) implantation, mediastinitis, length of hospital stay, and one-month mortality. The latter was defined as death from a cardiovascular cause related to any adverse event inherent to the prosthetic implant. Finally, pre- and post-prosthetic implant valve gradient values were considered, as well as the incidence of valve thrombosis and prosthetic endocarditis within 30 days of surgery, and one-year mortality.

RESULTS

The cohort included 47 patients (42.6% male) who underwent rapid deployment aortic valve procedures, with a median age of 79.4 years (IQR 74.5–82.6). Only 5 patients were under 70 years of age. Mean BMI was 27.5 ± 4.56 kg/m². Hypertension was the most prevalent comorbidity (76.6%), followed by diabetes mellitus (21.3%) and atrial fibrillation (19.1%). In 23.4% of cases, patients had advanced functional class (NYHA III/IV), and the median STS score was 2.7 (IQR 1.83–4.32). (Table 1).

The procedures were successfully performed in 100% of cases. Most procedures were elective (93.6%), with no emergency cases or conversions to full sternotomy. The most used prosthesis sizes were 21 mm (38.3%) and 23 mm (29.8%). Median CPB time was 90 minutes (IQR 80–99), and median aortic clamping time 65 minutes (IQR 56–78.5). No valve explants or use of conventional valves were recorded, and the incidence of paravalvular leak was low, with two cases of mild leak and three cases of trivial leak. (Table 2).

In the postoperative period, the most common complication was atrial fibrillation, observed in 40.4% of patients. The only recorded reoperation for bleeding occurred in a 79-year-old patient, a few hours after admission to the intensive care unit, secondary to coagulopathy (no bleeding was observed at cannulation sites or from the aortotomy). Three cases of mediastinitis requiring subsequent mediastinal debridement were recorded. A single case of a major neurological event was recorded (hemorrhagic stroke 24 hours postoperatively in an 82-year-old patient, with no hemodynamic impact or neurological sequelae), and prolonged mechanical ventilation was rare (4.3%). No myocardial infarctions, need for IABP, or PM implantation due to AV block were reported. Median blood loss in the first 24 hours was 200 mL (IQR 142.5–252.5), and median transfusion requirement was 1 unit of red blood cells (IQR 0–2). Median hospital stay was 7 days (IQR 5–8). There were no deaths at 30 days, and only one death was recorded at one year (2.1%), corresponding to a case of septic shock secondary to prosthetic endocarditis 4 months after the initial surgery. (Table 3).

Mean preoperative valve area was 0.83 ± 0.41 cm². The maximum aortic gradient decreased from 73.9 ± 21.3 mmHg preoperatively to 17.2 ± 6.9 mmHg postoperatively (p<0.001), while mean gradient decreased from 44.5 ± 13.3 mmHg to 8.6 ± 3.7 mmHg (p <0.001). No cases of prosthetic thrombosis or prosthetic endocarditis were recorded within the first postoperative month. (Table 4)

DISCUSSION

Aortic stenosis is the most prevalent valvular heart disease, and given the increase in the number of elderly patients due to higher life expectancy the therapeutic approach progressively takes into account surgical risk, life expectancy, and prosthesis durability when selecting the optimal procedure. This must combine safety, low mortality, low surgical impact, rapid recovery and functional reintegration, along with prosthetic durability and favorable long-term hemodynamic outcomes. (2,3) In the era of TAVI, minimally invasive surgery (J- or T-shaped mini-sternotomy, RAT, transaxillary), together with the use of RDV, represents the surgical alternative that is comparable in terms of minimally invasive approach.

Data from the MISSION study (10)—the only prospective, multicenter study with a 6-month follow-up focused on minimally invasive surgery and RVD—successfully assessed the safety of this combination, reporting an early cardiovascular mortality rate of 0% and a long-term rate of 4.4%. Our series showed favorable results in this regard, with zero mortality within 30 days postoperatively and 2.1% at one year.

In terms of perioperative morbidity, minimally invasive approaches offer multiple advantages, stemming primarily from reduced surgical trauma. They decrease blood loss and polytransfusion, surgical site infections, the duration of mechanical ventilation, and length of hospital stay, while also providing aesthetic benefits and enabling rapid recovery. (11-14) These benefits could be offset by the technical difficulty involved in implanting a conventional valve in a confined space, leading to prolonged surgical times, clamping times, and CPB times—all of which are independent predictors of morbidity and mortality. (17,18) It is at this point that RDV play a fundamental role, especially due to their rapid balloon-expandable delivery mechanism, that shortens implantation times and facilitates this type of approach. This argument was supported by Borger et al., (15) who, in a multicenter comparative study, demonstrated that patients undergoing minimally invasive surgery with RDV had 24% reduction in clamping time compared to those undergoing surgery via full sternotomy with a conventional valve.

Although our series yielded clamping and CPB times comparable to those in large-scale international studies such as the TRANSFORM study (19)—in which the mean cross-clamp time in patients undergoing AVR via mini-sternotomy was 62.3 ± 25 min—there are reports of even shorter times, such as that by Schlömicher et al. (20), who reported clamping and CPB times of 26 ± 7 min and 56 ± 16 min, respectively—one of the lowest registries recorded. Nevertheless, our results did not affect the morbidity and mortality of the cohort, which could be attributed to the initial learning curve.

A notable feature of RDV is the higher incidence of PM implantation due to atrioventricular block, reported in the literature as approximately 5% to 13%. (21,22) This is related to patient-dependent factors, such as preoperative bundle branch block, hypertrophic cardiomyopathy, excessive annular decalcification, and factors inherent to prosthesis implantation. (23) This implantation system, which extends the valve to the subannular level, causes direct compression of the conduction system, similar to the mechanism observed during TAVI. Coti et al. demonstrated in their series of 700 patients who underwent RDV that right bundle branch block was the only independent factor associated with the need for permanent PM implantation (9.5%). (24) It should be noted that in our series, there were no cases requiring permanent PM implantation within the first postoperative month. Nevertheless, we believe that careful patient selection is important, and that patients with this conduction disorder should be excluded. Additionally, prosthesis oversizing should be avoided; and in cases of uncertainty regarding whether to implant a larger or smaller prosthesis, the smaller size should be chosen.

Regarding the design of the EDWARDS INTUITY prosthesis, it combines the excellent safety and long-term durability of the Carpentier Edwards-Perimount Magna Ease prosthesis platform (25,26) with a stainless-steel expandable balloon frame that anchors the system subannularly, similarly to the structure of the Sapien transcatheter aortic valve. This has a significant hemodynamic impact, explained primarily, on the one hand, by the absence of pledget-reinforced radial points and the “tobacco pouch” effect they create, thereby optimizing the effective orifice area (EOA); (27) and, on the other hand, because the left ventricular outflow tract—where the stainless-steel frame is anchored—is widened. This has a favorable effect on transprosthetic gradients, as evidenced by the TRITON study, (21) which demonstrated a sustained reduction in gradients with a mean postoperative value of approximately 10 mmHg and an effective orifice area of approximately 1.6 cm² at five-year follow-up. Similarly, the TRANSFORM registry, (19) in a cohort of more than 1000 patients, confirmed a significant and stable decrease in gradients (postoperative mean ~10–12 mmHg), reinforcing the reproducibility of the hemodynamic improvement observed with this prosthesis across different clinical scenarios. On the other hand, in patients at high risk of prosthesis-patient mismatch (PPM)—such as those with a small aortic annulus, a large body surface area, or need for a prosthesis smaller than 23 mm—use of 19- or 21-mm RDV prostheses have been shown to maintain adequate transvalvular gradients. With conventional prostheses, this same situation typically requires annular enlargement techniques, which increase operative morbidity and mortality.

In this regard, Coti et al., (29) in a cohort of 217 patients with a small aortic annulus, reported an incidence of moderate and severe PPM of 33% and 10%, respectively, for 19-mm prostheses, and 23% and 9% for 21-mm prostheses. These results highlight a hemodynamic advantage of RDV over TAVI, in which the incidence of severe PPM reaches approximately 40% in patients receiving prostheses of 23 mm or smaller. (30) The long-term stability of the prosthesis, particularly at the ventriculo-aortic junction and in the left ventricular outflow tract, raises questions about the clinical relevance of paravalvular leak in this type of valve. This condition is of particular interest, given that its presence has been consistently associated with increased mortality and long-term cardiovascular events. (28) In our series, no cases of moderate or severe leak were recorded, a relevant finding given the morbidity and mortality associated with this condition following any valve replacement or transcatheter implantation procedure. (10,15,19,21,27)

Conclusion

In our experience, the use of rapid deployment valves via a minimally invasive approach proved to be a safe technique with favorable short-term mortality outcomes and hemodynamic profile.

Conflicts of interest

None declared. (See authors’ conflicts of interest forms on the website)