Valve structure and survival in octogenarians having aortic valve replacement for aortic stenosis (+/- aortic regurgitation) with versus without coronary artery bypass grafting at a single US medical center (1993 to 2005)

Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021

BACKGROUND

 Transcatheter aortic valve implantation (TAVI) has gained worldwide acceptance and implementation as an alternative therapeutic option in patients with severe aortic valve stenosis unable to safely undergo surgical aortic valve replacement. This transformative technique places the radiologist in a key position in the pre-procedural assessment of potential candidates for this technique, delivering key anatomical information necessary for patient eligibility and procedural safety. Recent trials also provide encouraging results to potentially extend the indication to patients with safer risk profiles.

METHOD

 The review is based on a PubMed literature search using the search terms "transcatheter heart valve", "TAVI", "TAVR", "CT", "imaging", "MR" over a period from 2010-2020, combined with personal comments based on the author's experience.

RESULTS AND CONCLUSION

 CT plays a prominent role in the pre-procedural workup, delivering as a true 3D imaging modality optimal visualization of the complex anatomy of the aortic root with simultaneous evaluation of the patency of the different access routes. As such, the contribution of CT is key for the determination of patient eligibility and procedural safety. This input is supplementary to the contributions of other imaging modalities and forms an important element in the discussions of the Heart Valve Team. Knowledge of the procedure and its characteristics is necessary in order to provide a comprehensive and complete report. While the role of CT in the pre-procedural evaluation is well established, the contribution of CT and MR and the clinical significance of their findings in the routine follow-up after the intervention are less clear and currently the subject of intense investigation. Important issues remain, including the occurrence and significance of subclinical leaflet thrombosis, prosthetic heart valve endocarditis, and long-term structural valve degeneration.

KEY POINTS

  · CT plays a crucial role in evaluating transcatheter heart valve candidates. · Evaluation must include the dimensions of the aortic root and access paths. · The exact post-procedural role of CT and MRI has not yet been determined..

CITATION FORMAT

· Salgado R, El Addouli H, Budde RP. Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021. Fortschr Röntgenstr 2021; 193: 1411 - 1425.

Transcatheter Treatment of Bicuspid Aortic Valve Disease: Imaging and Interventional Considerations

Patients with bicuspid aortic valve disease have systematically been excluded from large randomized clinical trials investigating transcatheter aortic valve implantation (TAVI) due to their younger age, lower surgical risk and complex aortic anatomy. The asymmetric nature of the bicuspid valve orifice often accompanied by heavy regional calcification has led to concerns regarding valve positioning and expansion. Bicuspid aortic valve disease patients are at heightened risk of TAVI-related complications including coronary occlusion, aortic dissection and annular rupture, as well as the known risks of progressive aortopathy in these patients. These unique anatomical characteristics pose challenges for TAVI operators. However, with recent and ongoing refinements in implantation technique, improvements in pre-procedural imaging and iterations in device design, TAVI is emerging as a safe and feasible treatment option in this population. Paravalvular aortic regurgitation and high pacemaker rates have been the Achilles Heel for TAVI in bicuspid valve patients, yet newer generation devices are yielding promising results. Further studies are required before TAVI ultimately emerges as a viable option in low and intermediate surgical-risk patients with bicuspid valve disease. This review comprehensively summarizes the epidemiology, pathology and current evidence for TAVI in patients with bicuspid aortic valve disease. We also outline some practical tips for performing TAVI in these patients.

Impact of Valve Morphology on the Prevalence of Coronary Artery Disease: A Systematic Review and Meta-Analysis

Background

Literature studies suggested a lower prevalence of coronary artery disease (CAD) in bicuspid aortic valve (BAV) than in tricuspid aortic valve (TAV) patients. However, this finding has been challenged. We performed a meta‐analysis to assess whether aortic valve morphology has a different association with CAD, concomitant coronary artery bypass grafting (CABG), and postoperative mortality.

Methods and Results

Detailed search was conducted according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta‐Analyses) guideline to identify all patients with BAV or TAV and presence of CAD, concomitant myocardial surgical revascularization, and the postoperative mortality. Thirty‐one studies on 3017 BAV and 4586 TAV patients undergoing aortic valve surgery were included. BAV patients showed a lower prevalence of CAD (odds ratio [OR]: 0.33; 95% CI: 0.17, 0.65), concomitant CABG (OR, 0.45; 95% CI: 0.35, 0.59), and postoperative mortality (OR, 0.62; 95% CI: 0.40, 0.97) than TAV. However, BAV subjects were significantly younger than TAV (mean difference: −7.29; 95% CI: −11.17, −3.41) were more frequently males (OR, 1.61; 95% CI: 1.33, 1.94) and exhibited a lower prevalence of hypertension (OR, 0.58; 95% CI: 0.39, 0.87) and diabetes (OR, 0.71; 95% CI: 0.54, 0.93). Interestingly, a metaregression analysis showed that younger age and lower prevalence of diabetes were associated with lower prevalence of CAD (Z value: −3.03; P=0.002 and Z value: −3.10; P=0.002, respectively) and CABG (Z value: −2.69; P=0.007 and Z value: −3.36; P=0.001, respectively) documented in BAV patients.

Conclusions

Analysis of raw data suggested an association of aortic valve morphology with prevalence of CAD, concomitant CABG, and postoperative mortality. Interestingly, the differences in age and diabetes have a profound impact on prevalence of CAD between BAV and TAV. In conclusion, our meta‐analysis suggests that the presence of CAD is independent of aortic valve morphology.

Open issues in transcatheter aortic valve implantation. Part 1: patient selection and treatment strategy for transcatheter aortic valve implantation

An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.

Severe aortic stenosis and coronary artery disease

Coronary artery disease (CAD) and aortic stenosis (AS) share pathophysiological mechanisms and risk factors. Moreover, the prevalence of CAD increases among elderly patients with severe AS since disease progression is strongly associated with age for both CAD and AS. These factors contribute to the frequent coexistence of CAD and AS. Patients with concomitant AS and CAD are characterised by higher baseline risk profiles with a larger number of comorbidities as compared to patients with isolated AS. Therefore, adequate therapeutic strategies are crucial for the treatment of these patients. The number of patients undergoing concomitant coronary artery bypass grafting (CABG) and surgical aortic valve replacement (SAVR) doubled during the last decade. Moreover, the development and rapid integration of transcatheter aortic valve implantation (TAVI) into clinical practice in western European countries has further extended invasive treatment of AS to elderly high-risk patients not considered suitable candidates for SAVR, frequently presenting with CAD. The aim of this review article is to provide an overview on CAD prevalence, impact on clinical outcomes, and treatment strategies in patients with severe AS requiring SAVR or TAVI.

Adding coronary artery bypass grafting to aortic valve replacement increases operative mortality for elderly (70 years and older) patients with aortic stenosis

OBJECTIVE

This retrospective study aimed to determine the effect of simultaneous aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) on operative outcomes and long-term survival in elderly patients with a high prevalence of comorbidity.

METHODS

One hundred and fifty-seven elderly patients (70 years old or older) undergoing isolated AVR (n = 120) or combined AVR/CABG (n = 37) were evaluated. Operative outcomes were compared between the two surgical groups. Long-term survival was also compared between the groups using the Kaplan-Meier method and long-rank (Mantel-Cox) test.

RESULTS

Operative mortality was 0.8 % for the isolated AVR group and 5.4 % for the combined AVR/CABG group (p = 0.076). The length of the intensive care unit stay for the combined AVR/CABG group was significantly longer than that for the isolated AVR group (median: 40 vs. 21 h, p = 0.008). However, the occurrence rate of hospital complications, such as reoperation for bleeding, deep sternal infection, supra-ventricular arrhythmia, and neurological complications, was similar between the two groups. Actuarial survival at 3 and 5 years was 82.3 and 80.9 % for the isolated AVR group, and 88.3 and 73.0 % for the combined AVR/CABG group, respectively (p = 0.637).

CONCLUSIONS

The satisfactory operative and long-term results in our study support a more aggressive simultaneous coronary revascularization combined with AVR for aortic valve stenosis in elderly patients.

Natural history of adults with congenitally malformed aortic valves (unicuspid or bicuspid)

Appreciation of the frequency of the congenitally malformed aortic valve has come about during the last 50 years, a period during which aortic valve replacement became a predictably successful operation. Study of patients at necropsy with either a congenitally unicuspid (1 true commissure) or bicuspid (2 true commissures) valve in whom no aortic valve operation has been performed has not been conducted during these 50 years, to our knowledge. We studied 218 patients at necropsy with congenitally malformed aortic valves: 28 (13%) had a unicuspid valve and 190 (87%), a bicuspid valve. Their ages at death ranged from 21 to 89 years (mean, 55 yr), and 80% were men. Of the 218 adults, the aortic valve functioned normally during life in 54 (25%) and abnormally in 164 (75%): aortic stenosis in 142 (65%), pure aortic regurgitation without superimposed infective endocarditis (IE) in 2 (1%), and IE superimposed on a previously normally functioning aortic valve in 20 (9%). IE occurred in a total of 31 (14%) of the 218 patients: involving a previously normally functioning valve in 20 (65%) and a previously stenotic valve in 11 (35%). Of the 218 patients, at least 141 (65%) died as a consequence of aortic valve disease (124 patients) or ascending aortic tears with or without dissection (17 patients). An estimated 1% of the population, maybe higher in men, has a congenitally malformed aortic valve. Data from this study suggest that about 75% of them will develop a major complication. Conversely, and encouragingly, about 25% will go through life without a complication.

Outcome of patients aged ≥80 years undergoing combined aortic valve replacement and coronary artery bypass grafting: a systematic review and meta-analysis of 40 studies

AIM

This study was planned to evaluate the outcome of patients aged ≥80 years undergoing combined conventional aortic valve replacement (AVR) and coronary artery bypass grafting (CABG).

METHODS

This is a systematic review of the literature and meta-analysis of data on patients aged ≥80 years who underwent combined AVR and CABG.

RESULTS

The literature search yielded 40 observational studies reporting on 8,975 patients aged ≥80 years. Pooled proportion of immediate postoperative mortality was 9.7% (95% CI 8.4-11.1, 40 studies, 8,975 patients). Immediate mortality was 8.2% (95% CI 6.5-10.0) in 15 studies with a mid-date from 2000 to 2007 and 10.8% (95% CI 9.1-12.7) in 25 studies with a mid-date from 1982 to 1999 (P = .043). Postoperative stroke rate was 3.7% (95% CI 2.8-4.8, 12 studies, 2,770 patients), and postoperative implantation of pacemaker was 4.3% (95% CI 2.6-6.5, 5 studies, 535 patients). The mean length of stay in intensive care unit was 5.3 days (95% CI 3.3-7.3, 5 studies, 490 patients), and the mean length of in-hospital stay was 16.9 days (95% CI 12.4-21.4, 5 studies, 424 patients). One-, 3-, 5- and 10-year pooled survival rates after combined AVR and CABG were 83.2%, 72.9%, 60.8%, and 25.7%, respectively.

CONCLUSIONS

Conventional AVR and CABG in patients aged ≥80 years are associated with significant operative mortality and morbidity as well as prolonged in-hospital treatment. However, conventional surgery is associated with remarkably good late survival. This suggests that any alternative treatment modality must prove itself of being enough durable also in the very elderly.

Immediate and late outcome of patients aged 80 years and older undergoing isolated aortic valve replacement: a systematic review and meta-analysis of 48 studies

OBJECTIVE

This study was planned to evaluate the outcome of patients ≥80 years old undergoing isolated conventional aortic valve replacement (AVR).

METHODS

Systematic review of the literature and meta-analysis of data on octogenarians and nonagenarians who underwent isolated AVR were performed.

RESULTS

The literature search yielded 48 observational studies reporting on 13 216 patients ≥80 years old. Pooled proportion of immediate postoperative mortality was 6.7 % (95% CI 5.8-7.5, 47 studies, 13,092 patients), and it was 5.8% (95% CI 4.8-6.9) in 18 studies with a mid-date from 2000 to 2006 and 7.5% (95% CI 6.8-8.2) in 30 studies with a mid-date from 1982 to 1999 (P = .004). Pooled proportion of postoperative stroke was 2.4% (95% CI 2.1-2.7, 21 studies, 8,436 patients), that of postoperative dialysis was 2.6% (95% CI 1.6-3.8, 10 studies, 1,945 patients), and that of postoperative implantation of a pacemaker was 4.6% (95% CI 3.6-5.8, 6 studies, 1,470 patients). Pooled survival rates at 1, 3, 5, and 10 years after isolated AVR were 87.6%, 78.7%, 65.4%, and 29.7%, respectively.

CONCLUSIONS

Immediate postoperative mortality and morbidity after isolated AVR in patients ≥80 years old are rather low. Postoperatively mortality decreased even further in the most recent series. Importantly, isolated AVR in these high-risk patients was associated with good late survival. These findings suggest that advanced age alone cannot be considered as a contraindication to conventional isolated AVR and that any new valve prosthesis implanted in these patients should be durable enough to guarantee the results so far offered by conventional surgery.

The role of echocardiography in the evaluation and management of aortic stenosis in the older adult

Aortic stenosis is currently the most predominant valvular pathology in older adults. Signs and symptoms of aortic stenosis in this age-group may be difficult to recognize due to the decreased activity associated with aging and attribution of symptoms to other conditions. Echocardiography can be very helpful in the assessment of valvular structure and real time hemodynamic evaluation as well as in the progression of the disease over time. Unprecedented advances in echocardiography, including real time three-dimensional echocardiography, facilitate a comprehensive assessment of this condition and help in the decision-making process. Recent innovations in the percutaneous treatment of valvular diseases promise a revolution in the treatment of aortic stenosis especially in older adults.

[Multislice computed tomography in the selection of candidates for transcatheter aortic valve implantation]

Transcatheter aortic valve implantation is an emerging treatment option for severe symptomatic aortic stenosis in patients considered unsuitable for surgical valve replacement. The authors review the use of multislice computed tomography in the selection of candidates for transcatheter aortic valve replacement, procedural support and post-interventional follow-up. A single-center experience of the role of this imaging technique is also described. Multislice computed tomography is an essential imaging tool in the selection and exclusion of candidates for transcatheter aortic valve implantation, providing evaluation of coronary anatomy and the relationship of the coronary ostia with the aortic valve structure, and accurate analysis of the valve annulus and aortic root, left ventricular outflow tract, aorta and peripheral vascular access routes. Multislice computed tomography is also central to the choice of appropriate prosthesis size. In addition, it guides arterial puncture by image fusion techniques and enables correct prosthesis apposition to be verified. This review aims to describe the role of computed tomography in this increasingly common interventional valve procedure, providing an overview of current knowledge and applications.

Current state of symptomatic aortic valve stenosis in the Japanese elderly

BACKGROUND

There have been few reports regarding treatment selection and prognosis of symptomatic aortic valve stenosis (AS) in the elderly in Japan.

METHODS AND RESULTS

Sixty-one patients hospitalized between January 2000 and December 2007 for symptomatic severe AS were investigated. The average observation period was 27 months. Thirty-seven patients (61%) were diagnosed with AS for the first time on hospitalization. Thirty-six patients had onset of symptoms within 1 month before admission. Thirty-six patients received aortic valve replacement (group S) and 25 received medical therapy (group M). The patients in group M were older than those in group S (84.1 ± 5.3 years vs. 74.2 ± 4.6 years, P<0.001). Maximum flow velocity measured by echocardiography was lower in group M (4.5 ± 0.3 m/s vs. 4.9 ± 0.5 m/s, P<0 .01), but there was no difference in valve area between the 2 groups (0.62 ± 0.19 cm² vs. 0.57 ± 0.15 cm², P=0.12). One-year mortality rate derived from the Kaplan-Meier curve was higher in group M than group S (53.1% vs. 6.4%, respectively). On multivariate analysis, the only independent favorable prognostic factor was aortic valve replacement (HR: 0.02, 95%CI: 0.01-0.15, P<0.01).

CONCLUSIONS

Medical therapy is often selected for treatment of symptomatic AS in the elderly, but the prognosis is very poor. Symptomatic severe aortic stenosis should be treated surgically, or with transcatheter aortic valve implantation in cases with high surgical risk.

Transapical transcatheter off-pump aortic valve implantation

Transapical aortic valve implantation (TA-AVI) is a new minimally invasive technique for beating-heart off-pump AVI in high-risk patients. The procedure involves antegrade AVI using an oversizing technique with direct access and accurate positioning of a stent based transcatheter xenograft. Procedural steps include placement of femoral arterial and venous access wires, anterolateral minithoracotomy, placement of an epicardial pacing wire and two apical purse-string sutures. Valve implantation is performed off-pump under fluoroscopic and echocardiographic guidance with rapid ventricular pacing. This new technology is a promising alternative for selected elderly high-risk patients and seems to be associated with good outcome and a minimal stroke risk.

Is transapical aortic valve implantation really less invasive than minimally invasive aortic valve replacement?

BACKGROUND

Transcatheter valve implants currently draw their justification for use from reduction of perioperative risk. However, patient age and comorbidities are independent predictors of adverse outcome after aortic valve replacement, regardless of surgical approach. Therefore, it is unclear whether transapical aortic valve implantation really improves outcomes in high-risk patients.

METHODS

We included a total of 51 high-risk patients with severe aortic valve stenosis. Patients were allocated to transapical aortic valve implantation (n = 21) or minimally invasive aortic valve replacement via a partial upper sternotomy (n = 30), in a nonrandomized fashion. Patient age, preoperative comorbidities, and perioperative risk, expressed as logistic EuroSCORE (38% +/- 14% vs 35% +/- 9%), were matched between the 2 groups.

RESULTS

Early morbidity and mortality were comparable between groups, but transapical aortic valve implantation was associated with shorter operative time (P = .004), ventilation time (P < .001), intensive care unit stay (P < .001), and hospital stay (P < .001). Thirty-day mortality was 14% (n = 3) in the transcatheter group versus 10% (n = 3) in the surgical group. After a mean follow-up of 12 +/- 4 months (100% complete), there were a total of 5 (24%) deaths in the transapical group versus 5 (17%) deaths in the open surgery group. There was 1 intraoperative death in the transapical group versus none in the surgery group. In the transapical group, there were 2 re-explorations for bleeding, 2 intraoperative conversions, 1 case of prosthesis migration, and 2 impairments of coronary arteries. The surgery group included 1 re-exploration, 1 stroke, 1 pacemaker implantation for complete atrioventricular block, and 3 cases of atrial fibrillation.

CONCLUSIONS

Current data suggest a faster postoperative recovery after transapical aortic valve implantation, with early and late morbidity and mortality comparable with those of minimally invasive aortic valve replacement via partial upper sternotomy.

Aortic valve stenosis

Calcific aortic stenosis (AS) is primarily a disease of the elderly, possessing features that are biomechanical as well as systemic and inflammatory in nature, with risk factors and histopathology similar to atherosclerosis. To date no medical therapy has been shown to conclusively alter the progression of the disease, and for those with symptomatic AS, aortic valve replacement (AVR) is advocated. Factors that may alert the physician to an accelerated progression of calcific aortic valvular disease toward severe symptomatic AS include moderate aortic valve calcification, chronically dialyzed patients, and patients 80 years and older. There remains significant morbidity and mortality associated with AVR, and new techniques and technologies for AVR are being developed. For those who undergo successful AVR the long-term prognosis is good. A substantial number of patients with symptomatic AS present for anesthesia care for a variety of procedures. A thorough, modern understanding of AS and its course are necessary for the anesthesiologist to guide the patient through the perioperative period.

Valve structure and survival in quadragenarians having aortic valve replacement for aortic stenosis (+/-aortic regurgitation) with versus without coronary artery bypass grafting at a single US medical center (1993 to 2005)

The purpose of this study was to determine the effect of simultaneous coronary artery bypass grafting (CABG) and the influence of valve structure on both early and late survival in quadragenarians having aortic valve replacement (AVR) for aortic stenosis (AS) (with or without aortic regurgitation). We analyzed survival and valve structure in 48 adults (12 women), aged 40 to 49 years, having AVR for AS from 1993 through 2005 at Baylor University Medical Center, including 7 (15%) with and 41 (85%) without simultaneous CABG. Of the 48 quadragenarians, none died within 60 days of operation. Assessment of the relation between long-term survival and gender, aortic valve structure, preoperative severity of the AS, and concomitant CABG was not possible due to the low mortality. Four patients (9%) died >60 days after AVR: at 1.8, 6.3, 7.1, and 9.9 years, respectively. The aortic valve was congenitally unicuspid in 15 patients (31%), congenitally bicuspid in 32 (67%), and 3-cuspid in 1 (2%). In conclusion, of the 48 quadragenarians having AVR for AS, 47 (98%) had a congenitally malformed aortic valve, 60-day mortality was zero, and late mortality was low (8%).

Valve structure and survival in quinquagenarians having aortic valve replacement for aortic stenosis (+/-aortic regurgitation) with versus without coronary artery bypass grafting at a single US medical center (1993 to 2005)

The purpose of this study was to determine the effect of simultaneous coronary artery bypass grafting (CABG) and the influence of valve structure on both early and late survival in quinquagenarians having aortic valve replacement (AVR) for aortic stenosis (AS) (with or without aortic regurgitation). We analyzed survival and valve structure in 120 quinquagenarians having AVR for AS from 1993 through 2005 at Baylor University Medical Center, including 44 (37%) with and 76 (63%) without simultaneous CABG. Of the 120 patients, 2 (2%) died within 30 days of operation and none from 31 to 60 days postoperatively. Fifteen other patients (13%) died from >60 days to up to 13 years postoperatively. The unadjusted survival analysis showed that late survival was significantly better in the unicuspid/bicuspid valve structure group than in the tricuspid valve structure group (log-rank test p = 0.001), but that it was not affected by gender (male vs female), preoperative severity of the AS (transvalvular peak pressure gradient >50 vs < or =50 mm Hg), or by performance of CABG. The aortic valve was congenitally unicuspid in 18 patients (15%), congenitally bicuspid in 84 (70%), and 3-cuspid in 18 (15%). In conclusion, aortic valve structure affected the unadjusted late survival in quinquagenarians undergoing AVR for AS, but concomitant CABG, gender, and transvalvular peak systolic gradient had no effect.

Valve structure and survival in septuagenarians having aortic valve replacement for aortic stenosis (+/-aortic regurgitation) with versus without coronary artery bypass grafting at a single US medical center (1993 to 2005)

The purpose of this study was to determine the effect of simultaneous coronary artery bypass grafting (CABG) and the influence of valve structure on both early and late survival in septuagenarians having aortic valve replacement (AVR) for aortic stenosis (AS) (with or without aortic regurgitation). We analyzed valve structure in 424 septuagenarians having AVR for AS from 1993 through 2005 at Baylor University Medical Center, including 254 (60%) with and 170 (40%) without simultaneous CABG. Of the 424 patients, 8 (2%) had a congenitally unicuspid aortic valve, 179 (42%), a congenitally bicuspid aortic valve, 235 (55%), a 3-cuspid valve, and in 2 patients (1%) the valve structure was indeterminate. Survival data were available in 418 of the 424 patients: 23 (5.5%) died within 30 days of AVR and 9 other patients from 31 to 60 days after AVR (7.7% 60-day mortality). Sixty-day mortality was not affected by congenital valve abnormality (unicuspid/bicuspid 8.5% vs tricuspid 7.0%). In contrast, late survival (up to 13-year follow-up) was affected by valve structure: it was longer in the unicuspid/bicuspid valve structure group than in the tricuspid valve structure (hazard ratio 0.54, 95% confidence intervals 0.36 to 0.81). The hazard ratio was estimated after adjusting for concomitant CABG. In conclusion, aortic valve structure affected late, but not early survival in septuagenarians undergoing AVR for AS.