A new hope for aortic valve surgery: the rise of minimally invasive aortic valve replacement – a retrospective cohort study
Introduction: Minimally invasive aortic valve replacement (miniAVR) is increasingly adopted as an alternative to conventional AVR, offering reduced surgical trauma, improved cosmesis, accelerated recovery, and decreased transfusion requirements. (1) Despite these advantages driving its uptake, concerns regarding longer operative times, technical complexity, and limited operative exposure continue to hinder its wider dissemination. (2) This study aims to evaluate and directly compare perioperative outcomes of miniAVR versus conventional AVR in a contemporary cardiac surgical setting.
Patients and Methods: This retrospective cohort study was conducted at University Hospital Center Zagreb and included 1,649 patients who underwent full sternotomy AVR (n=1,096) or miniAVR (n=553) between 2010 and 2024. Group comparisons were performed using the chi-square test for categorical variables and the Mann-Whitney U test for continuous variables, with a significance threshold of p<0.05. Multivariable logistic regression was applied to categorical outcomes, while linear regression was used for continuous variables. Statistical analyses were conducted using SPSS.
Results: The median age was 69 years, with 59.1% male patients (Table 1). MiniAVR was associated with longer CPB (101 vs. 95 min, p<0.001) and ACC times (71 vs. 65 min, p<0.001) but shorter ventilation duration (7 vs. 8 hours, p<0.001). Stroke incidence was lower in miniAVR (0.6% vs. 1.2%, p=0.009), while pacemaker implantation was more frequent (2.35% vs. 1.92%, p<0.001). A summary of intraoperative and postoperative outcomes is provided inTables 2 and 3{ label needed for table-wrap[@id='t3'] }. Regression analysis confirmed that miniAVR independently predicted longer CPB (B=4.75, p=0.040) and ACC times (B=1.97, p<0.001), lower stroke risk (B=-0.018, p<0.001) and reduced sternal wound infections (B=-0.031, p<0.001). Differences between univariate and multivariate analyses suggest confounding by other perioperative factors, highlighting the importance of adjusted analyses in assessing outcomes in minimally invasive surgery. A full regression analysis is presented inTable 4.
TABLE 1 Demographic and clinical profiles of subjects undergoing isolated aortic valve replacement surgery.
| All subjects
(n=1649) | Full Sternotomy AVR (n=1096) | | Minimally Invasive AVR (n=553) | p-value |
|---|
| Age (years), median (IQR) | 69 (62-75) | 70 (64-75) | | 67 (60-73) | <0.001 |
| Female, n (%) | 675 (40.9) | 447 (40.8) | | 228 (41.2) | 0.862 |
| BMI (kg/m2), median (IQR) | 29 (25-32) | 29 (26-32) | | 29 (26-32) | 0.858 |
| EF (%), median (IQR) | 60 (52-65) | 60 (50-65) | | 60 (55-65) | 0.005 |
| BAV, n (%) | 510 (30.93) | 259 (23.63) | | 251 (45.39) | <0.001 |
| Preoperative AF, n (%) | 290 (17.6) | 217 (17.8) | | 73 (13.2) | <0.001 |
| Endocarditis, n (%) | 45 (2.7) | 37 (3.38) | | 8 (1.45) | 0.023 |
| CAD, n (%) | 430 (26.1) | 323 (29.6) | | 106 (19.2) | <0.001 |
| Hypertension, n (%) | 1200 (72.8) | 792 (72.3) | | 408 (73.8) | 0.537 |
| Diabetes mellitus, n (%) | 491(29.78) | 351 (32.03) | | 140 (25.32) | 0.006 |
| Dyslipidemia, n (%) | 814 (49.36) | 527 (48.08) | | 287 (51.9) | 0.126 |
| Smoking, n (%) | 399 (24.2) | 242 (22.08) | | 137 (24.77) | 0.598 |
| COPD, n (%) | 166 (10.07) | 119 (10.85) | | 47 (8.5) | 0.144 |
| Preoperative creatinine (mg/dL), median (IQR) | 83 (70-100) | 85 (69-105) | | 81 (71-97) | 0.305 |
| CKD, n (%) | 850 (51.55) | 578 (52.74) | | 272 (49.19) | 0.088 |
| Previous solid organ transplantation, n (%) | 20 (1.21) | 12 (1.1) | | 8 (1.45) | 0.461 |
| PVD, n (%) | 117 (7.1) | 89 (7.4) | | 36 (6.5) | 0.570 |
| Previous MI, n (%) | 91 (5.52) | 72 (6.57) | | 19 (3.44) | <0.001 |
| Stroke, n (%) | 189 (11.49) | 138 (12.59) | | 52 (9.4) | 0.009 |
| EuroSCORE II (%), median (IQR) | 2.46 (1.6-3.7) | 2.54 (1.75-3.96) | | 2.20 (1.49-3.15) | <0.001 |
| AVR: aortic valve replacement; miniAVR: minimally invasive aortic valve replacement; IQR: interquartile range; BMI: body mass index; EF: ejection fraction; BAV: bicuspid aortic valve; AF: atrial fibrillation; CAD: coronary artery disease; COPD: chronic obstructive pulmonary disease; CKD: chronic kindey disease; PVD: peripheral vascular disease; MI: myocardial infarction |
TABLE 2 Intraoperative characteristics of the study subjects.
| All subjects
(n=1649) | Full Sternotomy AVR (n=1096) | Minimally Invasive AVR (n=553) | p-value |
|---|
| ACC (min), median (IQR) | 67 (55-85) | 65 (56-88) | 71 (53-83) | <0.001 |
| CPB (min), median (IQR) | 97 (80-120) | 95 (77-117) | 101 (86-122) | <0.001 |
| AVR: aortic valve replacement; ACC: aortic cross-clamp; IQR: interquartile range; CPB: cardiopulmonary bypass |
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TABLE 3 Comparison of in-hospital outcomes between the study groups.
| All subjects (n=1649) | Full Sternotomy AVR (n=1096) | Minimally Invasive AVR (n=553) | p-value |
|---|
| MCS, n (%) | 36 (2.18) | 27 (2.46) | 9 (1.63) | 0.185 |
| Revision due to bleeding, n (%) | 49 (3.0) | 32 (2.92) | 17 (3.07) | 0.366 |
| Ventilation (hours), median (IQR) | 7 (5-11) | 8 (6-11) | 7 (5-10) | <0.001 |
| ICU stay (days), median (IQR) | 2 (1-2) | 2 (1-2) | 2 (1-2) | 0.771 |
| Need for pacemaker, n (%) | 34 (2.1) | 21 (1.92) | 13 (2.35) | <0.001 |
| POAF, n (%) | 545 (33.05) | 355 (32.39) | 190 (34.36) | 0.343 |
| Sternal wound infection, n (%) | 73 (4.43) | 44 (4.01) | 29 (5.24) | 0.090 |
| Stroke, n (%) | 20 (1.21) | 12 (0.8) | 8 (0.6) | 0.221 |
| AVR: aortic valve replacement; MCS: mechanical circulatory support; IQR: interquartile range; ICU: intensive care unit; POAF: postoperative atrial fibrillation |
TABLE 4 Multivariable regression analysis of factors associated with perioperative outcomes in full sternotomy aortic valve replacement and minimally invasive aortic valve replacement patients.
| B
Coefficient | 95% Confidence Interval | p-value |
|---|
| Aortic cross clamp | 1.968 | 0.915-3.563 | <0.001 |
| Cardiopulmonary bypass | 4.750 | 0.226-9.138 | 0.040 |
| Ventilation | -0.770 | -1.660-0.120 | 0.090 |
| Intensive care unit | -0.072 | 0.278-0.133 | 0.491 |
| Postoperative atrial fibrillation | -0.015 | -0.069-0.038 | 0.577 |
| Need for pacemaker | -0.036 | -0.057- -0.016 | <0.001 |
| Mechanical circulatory support | 3.671 | | 0.999 |
| Sternal wound infection | 0.031 | -0.043--0.019 | <0.001 |
| Stroke | 0.018 | 0.027--0.009 | <0.001 |
Conclusion: The increasing adoption of miniAVR reflects both patient preference and surgical advancements, underscoring its advantages over conventional AVR. By minimizing surgical trauma, accelerating recovery, and reducing stroke risk, miniAVR emerges as an optimal alternative in appropriately selected patients. Its clinical benefits position it as the preferred approach in high-volume centers, supporting enhanced perioperative outcomes and patient satisfaction.
