Influence of the On-X mechanical prosthesis on intermediate-term major thromboembolism and hemorrhage: A prospective multicenter study

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation: Part 2: Study results-prostheses, positions, and economic development

Objectives

The Prospective Randomized On-X Mechanical Prosthesis Versus St Jude Medical Mechanical Prosthesis Evaluation (PROSE) trial purpose was to investigate whether a current-generation mechanical prosthesis (On-X; On-X Life Technologies/Artivion Inc) reduced the incidence of thromboembolic-related complications compared with a previous-generation mechanical prosthesis (St Jude Medical Mechanical Prosthesis; Abbott/St Jude Medical). This second report documents the valve-related complications by individual prostheses and by Western and Developing populations.

Methods

The PROSE trial study was conducted in 28 worldwide centers and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The study protocol, and analyses of 10 demographic variables and 24 risk factors were published in detail in 2021.

Results

The total patient population (N = 855) included patients receiving an On-X valve (n = 462) and a St Jude Medical valve (n = 393). The overall freedom evaluation showed no differences at 5 years between the prostheses for thromboembolism or for valve thrombosis. There were also no differences in mortality. There were several differences between Developing and Western populations. The freedom relations at 5 years for mortality favored Western over Developing populations. Valve thrombosis was differentiated by position and site: aortic < mitral (P = .007) and Western < Developing (P = .005). In the mitral position there were no cases in Western populations, whereas there were 8 in Developing populations (P = .217).

Conclusions

The On-X valve and St Jude Medical valve performed equally well in the study with no differences found. The only differentiation occurred with valve thrombosis in the mitral position more than the aortic position and occurring in Developing more than Western populations. The occurrence of valve thrombosis was also related to a younger population possibly due to anticoagulation compliance based on record review.

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation : Part 1(Patient Dynamics): Preoperative demographics and preoperative and operative risk factors

OBJECTIVES

The PROSE trial purpose is to investigate whether the incidence of thromboembolic-related complications is reduced with a current generation mechanical prosthesis (On-X Life Technologies/CryoLife Inc.-On-X) compared with a previous generation mechanical prosthesis (St Jude Medical-SJM). The primary purpose of the initial report is to document the preoperative demographics, and the preoperative and operative risk factors by individual prosthesis and by Western and Developing populations.

METHODS

The PROSE study was conducted in 28 worldwide centres and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The preoperative demographics incorporated age, gender, functional class, etiology, prosthetic degeneration, primary rhythm, primary valve lesion, weight, height, BSA and BMI. The preoperative and operative evaluation incorporated 24 risk factors.

RESULTS

The total patient population (855) incorporated On-X population (462) and the St Jude Medical population (393). There was no significant difference of any of the preoperative demographics between the On-X and SJM groups. The preoperative and operative risk factors evaluation showed there was no significant difference between the On-X and St Jude Medical populations. The preoperative and operative risk factors by valve position (aortic and mitral) also documented no differentiation. The dominant preoperative demographics of the Western world population were older age, male gender, sinus rhythm, aortic stenosis, congenital aortic lesion, and mitral regurgitation. The dominant demographics of the Developing world population were rheumatic etiology, atrial fibrillation, aortic regurgitation, mixed aortic lesions, mitral stenosis and mixed mitral lesions. The Developing world group had only one significant risk factor, congestive heart failure. The majority of the preoperative and operative risk factors were significant in the Western world population.

CONCLUSIONS

The preoperative demographics do not differentiate the prostheses but do differentiate the Western and Developing world populations. The preoperative and operative risk factors do not differentiate the prostheses BUT do differentiate the Western and Developing world populations.

Successful Explant of a Ball and Cage Mitral Valve Prosthesis 48 Years After Initial Implant

A 58-year-old female had undergone previous mechanical mitral replacement with a Starr-Edwards ball and cage valve (Edwards Lifesciences, Irvine, CA) at 11 years of age for rheumatic disease. The valve functioned well until pannus resulted in prosthetic valve stenosis with class IV dyspnea and pulmonary hypertension. She underwent reoperative mitral replacement with an On-X mechanical mitral prosthesis (Cryolife, Kennesaw, GA) 48 years after initial implantation. To our knowledge, this case represents the longest known implant period of a ball and cage mitral valve in the literature. This presentation highlights the durability of this historic prosthesis, along with the role of reoperative surgery decades after initial implantation.

Long-Term Clinical Outcomes of the On-X Mechanical Prosthetic Valve in the Aortic or Mitral Position - A Single-Center Experience of up to 20 Years' Follow up

BACKGROUND

This study evaluated the long-term outcomes for up to 20 years after On-X mechanical valve implantation in the left side of the heart.Methods and Results:Between 1999 and 2015, 861 patients (mean age=51.6±10.9 years) who underwent prosthetic valve replacement using the On-X valve in the aortic or mitral position were enrolled (aortic=344, mitral=325, double=192). The mean clinical follow-up duration was 10.5±5.3 (median 10.9) years. Operative mortality occurred in 26 patients (3.0%), and linearized late cardiac mortality was 0.9%/patient-year without an intergroup difference. Linearized thromboembolism, bleeding, prosthetic valve endocarditis, non-structural valve deterioration (NSVD), and reoperation rates were 0.8%/patient-year, 0.6%/patient-year, 0.2%/patient-year, 0.5%/patient-year, and 0.5%/patient-year, respectively. Prosthetic valve endocarditis was more frequent after double valve replacement than after aortic or mitral valve replacement (P=0.008 and 0.005, respectively). NSVD and reoperation rates were significantly lower aortic valve replacement than after mitral or double valve replacement (P=0.001 and 0.002, P=0.001 and <0.001, respectively). Valve replacement in the mitral position was the only risk factor for NSVD (hazard ratio [95% confidence interval]=5.247 [1.608-17.116], P=0.006).

CONCLUSIONS

On-X valve implantation in the left side heart had favorable clinical outcomes with acceptable early and late mortality and a low incidence of prosthetic valve-related complications. Particularly in the aortic position, the On-X valve had better long-term non-structural durability.

Effect of post-operative anticoagulation management in patients who have undergone On-X mechanical heart valve replacement surgery on post-discharge warfarin therapy

WHAT IS KNOWN AND OBJECTIVE

We evaluated the effect of the proportion of time maintained within the target international normalized ratio (INR) postoperatively in hospitalized patients who underwent On-X mechanical heart valve replacement on warfarin therapy after discharge.

METHODS

Inclusion was patients who were ≥18 years, received warfarin for a minimum of 10 days without any interruptions during hospitalization and followed by the anticoagulation service (ACS) clinic after discharge between June 2006 and June 2016. Patients were excluded if they had incomplete medical records, INR goal changes, known as warfarin resistance, transferred to another facility or expired during the study. The patients were divided into 3 groups according to the proportion of time maintained within therapeutic INR range (TTR) from day 4 to 10 of warfarin initiation (low: <30%, moderate: ≥30% to <70%, and high: ≥70%). The number of days needed to reach target INR for 2 consecutive measurements after discharge and the number of ACS visits was compared among the groups.

RESULTS AND DISCUSSION

Among 539 postoperative patients, 273 were included. The baseline demographics were similar among the 3 groups. The mean time needed to reach target INR for 2 consecutive measurements was 68.6 ± 106.1 days. The low group required time needed to reach target INR for 2 consecutive measurements of 94.0 ± 140.9 days compared with 44.8 ± 57.1 days in the high group (P = .007). Additionally, the low group had more ACS visits than the high group (low, 6.6 ± 5.2 vs high, 4.6 ± 3.9; P = .025). Patient compliance affected the time needed to reach target INR for 2 consecutive measurements (compliant, 42.36 ± 58.5 days vs non-compliant, 132.0 ± 157.1 days, P < .001).

WHAT IS NEW AND CONCLUSION

The study implicated that high postoperative TTR would reduce the time to require post-discharge target INR and the number of ACS visits.

Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement

BACKGROUND

The burden oral anticoagulation is a limitation of mechanical valve prostheses.

OBJECTIVES

The aim of this study was to test whether patients could be safely managed with dual-antiplatelet therapy (DAPT) (aspirin 325 mg and clopidogrel 75 mg) or lower warfarin after On-X mechanical aortic valve replacement (mAVR).

METHODS

PROACT (Prospective Randomized On-X Anticoagulation Trial) (n = 576) is a multicenter (41 sites) noninferiority trial. From June 2006 through February 2014, 201 patients ≥18 years of age without thromboembolic risk factors undergoing mAVR were randomized to receive DAPT (n = 99) or standard warfarin plus aspirin (n = 102) 3 months after mAVR (low-risk arm). From June 2006 through October 2009, 375 patients with 1 or more thromboembolic risk factors were also randomized to lower intensity warfarin plus aspirin (international normalized ratio 1.5 to 2.0; n = 185) or standard warfarin plus aspirin (international normalized ratio 2.0 to 3.0; n = 190) 3 months after mAVR (high-risk arm).

RESULTS

The low-risk arm was terminated for excess cerebral thromboembolic events (3.12% per patient-year vs. 0.29% per patient-year, p = 0.02) in the DAPT group at up to 8.8-year follow-up (631.6 patient-years), with no differences in bleeding or all-cause mortality. High-risk arm patients experienced significantly lower major (1.59% per patient-year vs. 3.94% per patient-year, p = 0.002) and minor (1.27% per patient-year vs. 3.49% per patient-year, p = 0.002) bleeding up to 8.7-year follow-up (2,035.2 patient-years), with no differences in thromboembolism (0.42% per patient-year vs. 0.09% per patient-year, p = 0.20) and all-cause mortality.

CONCLUSIONS

DAPT was associated with higher rates of thromboembolism and valve thrombosis compared with control in the low-risk arm. International normalized ratios were safely maintained at 1.5 to 2.0 in high-risk patients, without differences in mortality or thromboembolic complications. (Randomized On-X Anticoagulation Trial [PROACT]; NCT00291525).

On-X mitral valve replacement: a single-centre experience in 318 patients

OBJECTIVES

If mitral valve repair is not feasible, mitral valve replacement remains the only option. Based on our overall experience with the On-X mitral valve, the aim of this study was to investigate early and late outcomes after mitral valve replacement using this latest generation prosthesis.

METHODS

From 1998 to 2016, 600 patients received an On-X prosthesis in the mitral position. Of them, we excluded all patients who had combined aortic procedures and retrospectively analysed 318 consecutive patients who had a mitral valve replacement. Associated procedures (53.5%) were tricuspid valve repair, coronary artery bypass graft and the maze procedure. The mean follow-up time was 5.6 ± 4.0 years.

RESULTS

The overall hospital mortality rate was 4.4%, including acute cases of ischaemic mitral regurgitation (9.4%) and infective endocarditis (9.4%). Survival rates at 1, 3, 5 and 10 years were 97.8 ± 1.0%, 92.4 ± 1.7%, 88.4 ± 2.2% and 70.9 ± 4.0%, respectively. Independent predictors of late mortality were hypertension [hazard ratio (HR) 1.91; P = 0.027], chronic obstructive pulmonary disease (HR 2.91; P = 0.003) and chronic renal failure (HR 5.27; P < 0.001). Freedom from reoperation was 99.3 ± 0.5%, 98.4 ± 0.8%, 97.2 ± 1.2% and 92.5 ± 2.4% at 1, 3, 5 and 10 years, respectively. At follow-up, 8.5% events were recognized as thromboembolic or haemorrhagic events; freedom from events related to anticoagulation therapy at 1, 3, 5 and 10 years was 99.0 ± 0.6%, 96.8 ± 1.1%, 93.7 ± 1.8% and 89.0 ± 2.7%, respectively.

CONCLUSIONS

According to the results of this observational study, the unique design of the On-X valve works well with mitral valve diseases of various aetiologies, especially in cases with an unfavourable anatomy. This prosthesis also guarantees safe long-term durability associated with a low incidence of thromboembolism.

Antithrombotic Management of Patients With Prosthetic Heart Valves

Valvular heart disease is a major public health issue. The prevalence of valvular heart disease is expected to increase due to an aging population. Valve dysfunction manifests as valve stenosis, regurgitation, or both due to various etiologies. Valve repair and replacement are the main treatment options for severe valve dysfunction. Valve replacement is achieved by using either a mechanical or a bioprosthetic valve. Mechanical valves are more durable but require lifelong anticoagulation with associated complications. Bioprosthetic valves usually require anticoagulation only transiently after implantation but are less durable and degenerate more rapidly. In this article, we discuss antithrombotic regimens in persons after valve operations. We discuss general issues and antithrombotic recommendations for patients undergoing surgical bioprosthetic valve replacement, mechanical valve replacement (including different regimens for different positions and types of mechanical valves), mitral valve repair, and transcatheter aortic valve replacement. In addition, we discuss the antithrombotic management of patients in special circumstances, including patients with mechanical valves who have recurrent bleeding or thrombotic events, patients with mechanical valves undergoing surgery, and pregnant women with mechanical valves.

Functional mitral stenosis following mitral valve repair

PURPOSE OF REVIEW

This review summarizes the evidence describing functional mitral stenosis (MS) following surgical mitral valve repair.

RECENT FINDINGS

Functional MS is an evolving concept and has been implicated in the repair of functional and organic mitral regurgitation. Following repair of functional mitral regurgitation, an elevation in peak transmitral gradient and pulmonary artery pressure has been observed under physiologic stress. These changes have been associated with worse functional status early after restrictive annuloplasty. Following repair of organic mitral regurgitation, functional MS has also been observed and appears associated with worse functional status late after surgery.

SUMMARY

Because repair of functional mitral regurgitation commonly involves restrictive annuloplasty, the issue of functional MS must be weighed against the benefits and durability of repair. Functional MS following repair of degenerative mitral regurgitation, however, may be modifiable. Research evaluating various repair techniques and their impact on functional MS following repair of organic is ongoing.

On-X versus St Jude Medical Regent mechanical aortic valve prostheses: early haemodynamics

Objective

We aimed to compare the early haemodynamic data of the On-X and St Jude Medical (SJM) Regent bileaflet mechanical prostheses in the aortic position.

Methods

A retrospective study was performed using data collected prospectively for a national database. Thirty-three patients who had aortic On-X valve (On-X group) and 33 matched patients who had aortic SJM Regent valve (SJM group) were included. The intraoperative and early postoperative data were collected. The same echocardiographer reviewed all the echocardiograms and obtained the required parameters.

Results

The peak gradient across the prosthetic valve was comparable between the two groups except for the labelled valve size of 25 mm for which the On-X group had lower peak gradient when compared with the SJM group. Mean gradients and effective orifice area indices of the two valve types within each valve size subgroup were comparable.

Conclusions

The current study confirms that in the early postoperative period, the two valve types had comparable haemodynamic outcomes.

Advances in the management of severe aortic stenosis

BACKGROUND

Recent developments in the management of severe aortic stenosis have resulted in a paradigm shift in the way we view the condition. Patients previously denied intervention in the form of surgical aortic valve replacement (SAVR) are now candidates for transcatheter aortic valve implantation and the risk and age profiles of those undergoing SAVR are rising with the ageing population. This review article is designed to provide an overview of developments in the surgical management of severe aortic stenosis. We also discuss the expanding role of minimally invasive surgical approaches to outline the current techniques available to treat patients with severe aortic stenosis.

METHODS

PubMed was searched using the terms 'severe aortic stenosis', 'surgical aortic valve replacement', 'transcatheter aortic valve replacement', 'mechanical aortic valve replacement' and 'sutureless aortic valve replacement'. Selection of articles was based on peer review, journal and relevance. Where possible articles from high-impact factor peer review journals were included.

RESULTS

Minimally invasive operative approaches include mini-sternotomy and mini-thoracotomy. Sutureless aortic prostheses reduce aortic cross-clamp time and cardiopulmonary bypass time; however, long-term follow-up data are unavailable at this time. Mechanical prostheses are advised for those under 60.

CONCLUSION

Multiple advances in the surgical management of aortic stenosis have occured in the past decade. An evolving spectrum of surgical and transcatheter interventions is now available depending on patient age and operative risk.

Anticoagulation dilemma in a high-risk patient with On-X valves

Thromboembolism continues to be a major concern in patients with mechanical heart valves, especially in those with unsatisfactory anticoagulation levels. The new On-X valve (On-X Life Technologies, Austin, TX, USA) has been reported as having unique structural characteristics that offer lower thrombogenicity to the valve. We report a case where the patient received no or minimal systemic anticoagulation after placement of On-X mitral and aortic valves due to development of severe mucosal arterio-venous malformations yet did not show any evidence of thromboembolism. This case report reinforces the findings of recent studies that lower anticoagulation levels may be acceptable in patients with On-X valves and suggests this valve may be particularly useful in those in whom therapeutic levels of anticoagulation cannot be achieved due to increased risk of bleeding.

Hemorrhage as a life-threatening complication after valve replacement in end-stage renal disease patients

OBJECTIVE

Hemodialysis patients have an increased risk of hemorrhage compared to other patients. This study reports the frequencies of hemorrhage and its impact on the survival of hemodialysis patients after valve replacement.

METHODS

A total of 77 consecutive dialysis patients who underwent prosthetic valve surgery from 1991 to 2011 were retrospectively reviewed. Their mean age was 65.8 ± 9.2 years. Forty-three patients (56%) were male. Fifty-nine patients (77%) had aortic valve replacement, and 23 patients (30%) had mitral valve replacement. Bioprosthetic valves were used in 17 patients (22%).

RESULTS

There were seven in-hospital mortalities (9.1%). The overall estimated Kaplan-Meier survival after 3, 5 and 7 years was 66.6 ± 5.6, 51.1 ± 6.3 and 34.4 ± 6.8%, respectively. Seventeen (22%) bleeding events were observed (5.9% per patient-years) in the follow-up period. Six of the nine patients with cerebral hemorrhages and two of the six with gastrointestinal hemorrhages died. There were no differences in the frequencies of hemorrhage between the patients treated with bioprostheses and mechanical valves.

CONCLUSIONS

This study found that 22% of dialysis patients had hemorrhagic events after valve replacement, and approximately half of them died. Particularly, cerebral hemorrhage was fatal and two thirds of the patients died. So we should meditate the methods to reduce hemorrhage. Therefore, new methods to reduce the risk of hemorrhage are urgently needed.

Clinical evaluation of new heart valve prostheses: update of objective performance criteria

This article summarizes the long-term clinical results of the Food and Drug Administration-approved heart valves, provides current updates to the objective performance criteria (OPC) used to evaluate new heart valve prostheses, and documents the steps that the International Organization for Standardization Committee used to arrive at the updated OPC. Data were extracted from 19 Food and Drug Administration summaries of safety and effectiveness data reports (31 series) and 56 literature articles (85 series) published from 1999 to 2012. The OPC were calculated for five valve-related complications by valve type (mechanical and bioprosthetic) and valve position (aortic and mitral).

Single center experience with the Sorin Bicarbon prosthesis: a 17-year clinical follow-up

OBJECTIVE

To evaluate the long-term results of aortic valve replacement (AVR) and mitral valve replacement (MVR) with the Sorin Bicarbon prosthesis (SBP).

METHODS

Five hundred seven patients (306 men, 201 women), mean age 62±10 years (range, 21-86 years), received an SBP between 1994 and 2000; AVR was performed in 344 (67%) and MVR in 163 (33%). The main concomitant procedure was coronary artery grafting in 79 patients (16%). Follow-up was 99% complete; mean follow-up was 12.7±4.0 years with a cumulative duration of follow-up of 6475 patient-years in the entire group (4348 patient-years for AVR and 2124 patient-years for MVR).

RESULTS

Hospital mortality was 2.7% (AVR, 2.03%; MVR, 4.3%). There were 169 late deaths (AVR, 128; MVR, 41). Actuarial survival at 17 years is 49.7%±5.3% for AVR and 62.0%±6.1% for MVR. At the last follow-up, 310 survivors (199 AVR, 111 MVR) are in New York Heart Association functional class I or II. At 17 years, actuarial freedom from valve-related deaths, embolism, and bleeding is 89.8%±4.8%, 85.8%±5.4%, and 96.2%±1.2% after AVR, and 91.9%±3.9%, 96.3%±1.8%, 95.0%±2.9% after MVR. Reoperation was required in 5 patients with AVR (thrombosis in 4 and perivalvular leak in 1). Actuarial freedom from reoperation is 98.1%±0.8% after AVR and 100% after MVR; freedom from endocarditis is 100% after AVR and 99.2%±0.7% after MVR. No cases of intrinsic structural valve failure were observed.

CONCLUSIONS

The SBP has shown excellent results in terms of clinical improvement and freedom from valve-related complications, even up to 17 years after AVR and MVR. It therefore seems to be a safe option whenever a mechanical prosthesis is needed.

Aortic Valve Insufficiency in the Teenager and Young Adult

The contents of this article were presented in the session “Aortic insufficiency in the teenager” at the congenital parallel symposium of the 2013 Society of Thoracic Surgeons (STS) annual meeting. The accompanying articles detail the approaches of aortic valve repair and the Ross procedure.1,2 The current article focuses on prosthetic valve replacement. For many young patients requiring aortic valve surgery, either aortic valve repair or a Ross procedure provides a good option. The advantages include avoidance of anticoagulation and potential for growth. In other patients, a prosthetic valve is an appropriate alternative. This article discusses the current state of knowledge regarding mechanical and bioprosthetic valve prostheses and their specific advantages relative to valve repair or a Ross procedure. In current practice, young patients requiring aortic valve surgery frequently undergo valve replacement with a prosthetic valve. In STS adult cardiac database, among patients ≤30 years of age undergoing aortic valve surgery, 34% had placement of a mechanical valve, 51% had placement of a bioprosthetic valve, 9% had aortic valve repair, and 2% had a Ross procedure. In the STS congenital database, among patients 12 to 30 years of age undergoing aortic valve surgery, 21% had placement of a mechanical valve, 18% had placement of a bioprosthetic valve, 30% had aortic valve repair, and 24% had a Ross procedure. In the future, the balance among these options may be altered by design improvements in prosthetic valves, alternatives to warfarin, the development of new patch materials for valve repair, and techniques to avoid Ross autograft failure.

Aortic biological valve prosthesis in patients younger than 65 years of age: transition to a flexible age limit?

OBJECTIVES

Guidelines proposed bioprosthesis implantation for aortic valve disease if the patients were at least 65 years old at the time of surgery, with a trend towards even younger patients in recent years. Considering the adverse effects of lifetime anticoagulation, new biological valves (less prone to degeneration) and new technologies may lead patients and surgeons to different choices. Therefore, it is interesting to analyse the results of aortic bioprosthetic valve replacement in patients aged <65 years at the time of surgery.

METHODS

From January 2000 to December 2010, 84 patients aged <65 years at the time of surgery had undergone an aortic bio-prosthetic valve replacement. A mid-term follow-up [(FU) mean FU time: 54.4 ± 39.2 months] was done in August 2011 in all patients (FU completeness: 100%). Results were compared with patients who had a mechanical prosthetic aortic valve replacement during the same period.

RESULTS

The reoperation rate for structural valve degeneration (SVD) of bioprostheses was 6% and occurred exclusively among patients <56 years. Contraindications for anticoagulation determined the choice of a bioprosthesis among 83% of these patients. The personal preference to avoid anticoagulation was the leading cause in 68% of the older patients (56-65 years). Neurological complications occurred more frequently in the mechanical control group.

CONCLUSIONS

Reoperations for SVD after bioprosthesis implantation occurred exclusively among younger patients (<56 years), not suitable for systemic anticoagulation. Previous studies, together with our experience, are in favour of an age limit between 56 and 60 years, taking into consideration alternative transcatheter approaches to SVD treatment.

Clinical event rates with the On-X bileaflet mechanical heart valve: a multicenter experience with follow-up to 12 years

OBJECTIVE

The aim of the study was to establish clinical event rates for the On-X bileaflet mechanical heart valve (On-X Life Technologies Inc, Austin, Tex) using an audit of data from the 3 centers within Europe with the longest history of implanting.

METHODS

All patients receiving the On-X valve between March 1, 1998, and June 30, 2009, at 3 European centers were studied. Data were collected using questionnaire and telephone surveys augmented by outpatient visits and examination of clinical records.

RESULTS

There were 691 patients, with a mean age of 60.3 years, who received 761 valves in total: 407 mitral valve replacements, 214 aortic valve replacements, and 70 aortic + mitral valve replacements (dual valve replacement). Total follow-up was 3595 patient-years, with a mean of 5.2 years (range, 0-12.6 years). Early (≤ 30 days) mortality was 5.4% (mitral valve replacement), 0.9% (aortic valve replacement), and 4.3% (dual valve replacement). Linearized late (>30 days) mortality expressed per patient-year was 3.6% (mitral valve replacement), 2.2% (aortic valve replacement), and 4.1% (dual valve replacement), of which valve-related mortality was 0.5% (mitral valve replacement), 0.2% (aortic valve replacement), and 1.8% (dual valve replacement). Late linearized thromboembolism rates were 1.0% (mitral valve replacement), 0.6% (aortic valve replacement), 1.8% (dual valve replacement). Bleeding rates were 1.0% (mitral valve replacement), 0.4% (aortic valve replacement), and 0.9% (dual valve replacement). Thrombosis rates were 0.1% (mitral valve replacement), 0% (aortic valve replacement), and 0.3% (dual valve replacement). Reoperation rates were 0.6% (mitral valve replacement), 0.2% (aortic valve replacement), and 1.2% (dual valve replacement).

CONCLUSIONS

The On-X valve has low adverse clinical event rates in longer-term follow-up (mean 5.2 years and maximum 12.6 years).