BEST EVIDENCE TOPIC – CONGENITAL

Interactive CardioVascular and Thoracic Surgery 18 (2014) 661–666 doi:10.1093/icvts/ivt541 Advance Access publication 30 January 2014

Is there a role for mechanical valve prostheses in pulmonary valve replacement late after tetralogy of Fallot repair? Jonathan Raihan Abbas* and J. Andreas Hoschtitzky Congenital Heart Surgery, Adult Congenital Heart Disease Unit, Central Manchester Foundation Trust, Manchester, UK * Corresponding author. Congenital Heart Surgery, Adult Congenital Heart Disease Unit, Central Manchester Foundation Trust, Manchester, UK. Tel: +44-161-9010122; fax: +44-161-2768522; e-mail: [email protected] ( J.R. Abbas). Received 7 June 2013; received in revised form 3 November 2013; accepted 3 December 2013

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: What is the role of mechanical valve prostheses in pulmonary valve replacement late after tetralogy of Fallot (TOF) repair? Altogether more than 30 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. In addition to this, two papers were found by searching the reference lists of the relevant papers. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude from the best evidence available that mechanical prosthetic valves do play a role in patients who require pulmonary valve replacement late after repair of TOF. With adequate anticoagulation, they represent a safe alternative to biological valves. Although the literature is very limited, in terms of patient numbers, many of the papers demonstrate an acceptable early mortality rate. There is significant variability in the regimes of anticoagulation in these patients, and the overall reported rate of valvar thrombosis, thromboembolic events and major haemorrhagic complications has also been variable. The overall rate of valvar thrombosis and other thromboembolic events is promising. Thrombotic events were often attributed to poor adherence to the anticoagulation regime. Conversely, 3 papers recorded no thromboembolic events during the followup period. Three papers recorded major haemorrhagic events during their follow-up period and concluded that these were a rare outcome. When appropriate anticoagulation is adhered to, mechanical pulmonary prostheses appear to be relatively safe in patients late after repair of TOF. We have also found that the rationale for insertion of mechanical valves in the pulmonary position late after TOF repair varies across centres is still controversial. Furthermore, their use in patients with concomitant pulmonary arterial stenoses may be less advisable as this will prevent future percutaneous interventions of the pulmonary arterial tree. More research is required to accurately compare the haemodynamic properties of mechanical valves in the pulmonary position compared with other valves. Additionally, a more consistent follow-up of these patients in terms of echocardiographic, valve-related and warfarin-related complications is needed. With this information, clearer conclusions may be drawn when considering their role. Keywords: Pulmonary valve replacement • Outcome • Survival • Complication • Durability • Mortality • Tetralogy of Fallot

INTRODUCTION A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1].

THREE-PART QUESTION What is the role of [mechanical valve prostheses] in [ patients undergoing pulmonary valve replacement] late after [tetralogy of Fallot repair]?

subsequently a tissue pulmonary valve replacement and pulmonary artery reconstruction. Later on she developed pulmonary valve endocarditis and required a homograft right ventricular to pulmonary artery conduit. She now has severe mixed prosthetic valve disease, right ventricular dysfunction and symptoms of breathlessness. An attempt at percutaneous valve implantation was not possible as the landing zone for the Medtronic Melody® valve was too short. She requires a fifth sternotomy, but would rather not have any further operations following this, as the risks are becoming greater.

CLINICAL SCENARIO

SEARCH STRATEGY

A 44-year old female patient who was born with tetralogy of Fallot with major aorto-pulmonary collaterals had undergone previously four sternotomies, including a primary tetralogy repair, then a repair of residual right ventricular outflow tract obstruction and

Medline 1950 to June 2013 using PubMed interface. (‘mechanical valve’ or ‘mechanical prosthesis’) and (‘pulmonary valve replacement’ or ‘pulmonary regurgitation’ or ‘tetralogy of Fallot’ or ‘TOF’ or ‘pulmonary stenosis’).

© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

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Abstract

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SEARCH OUTCOME Thirty papers were found using the reported search. From these, nine papers were identified that provided the best evidence to answer the question. In addition to this, two papers were found by searching the reference lists of the relevant papers. These are presented in Table 1.

RESULTS Hörer et al. [2] retrospectively compared the haemodynamic properties of 19 patients who had a pulmonary valve replacement (PVR) with a mechanical valve with those of 19 who had a biological valve. The patients were matched for age, sex and followup time. With statistical significance, they concluded that mechanical valves were initially better but declined faster. There was a high ratio of thrombosed mechanical valves. The authors concluded that mechanical valves may have a role in patients who are already on lifelong anticoagulation. Shin et al. [3] conducted a study looking at the medical records of 37 patients who had a PVR with a mechanical valve. The durability of the mechanical valves was excellent and the rates of thromboembolic events and bleeding due to anticoagulation were low. A cohort study performed by Stulak et al. [4] retrospectively analysed 54 patients who had PVR with mechanical valves over a period of 40 years. It showed that mechanical valves provided a high level of durability with very low risks of anticoagulation in the long term. Dos et al. [5] performed a study with 22 consecutive patients undergoing mechanical PVRs. They showed excellent durability, again with very low levels of anticoagulant complications. They suggest that they may be a viable alternative to biological valves. Tokunaga et al. [6] reviewed 18 patients who underwent an isolated PVR with a biological prosthesis and 6 who had a mechanical valve over a 27-year period. They concluded that there was a higher rate of valve thrombosis in the mechanical valve cohort. There was no statistically significant difference between the eventfree survival rates between the two groups. Waterbolk et al. [7] performed a retrospective review on 28 PVRs with mechanical valves. This series refutes the bad reputation that mechanical valves in the pulmonary position have. They have observed a much lower than expected rate of reoperation and no thromboembolic events were noted. Ovcina et al. [8] conducted a prospective study involving 24 patients who had mechanical pulmonary valves implanted. MRI was used to regularly follow these patients both during the preoperative and postoperative periods. This study demonstrated promising results. There was no evidence of valval dysfunction in the follow-up period and the rate of thromboembolic events was very low. In a retrospective cohort study, Dreosola et al. [9] analysed the outcomes of 4 TOF patients who had a PVR late after TOF repair. The mean follow-up time was 11 years. There was no mortality and no evidence of valvar dysfunction or rhythm disturbance during the lengthy follow-up interval. All patients remained symptomatically well. Reiss et al. [10] conducted a retrospective cohort study with 68 congenital heart disease patients with mechanical valves in situ.

Thirty-three patients had TOF. The aim of this study was to evaluate the efficacy of anticoagulation in this population. Valve thrombosis occurred in 3 TOF patients (9.1%). Mechanical valves implanted in the right side of the heart had a higher rate of valve thrombosis than valves in the left side over a mean follow-up of 72 months (range 6–132 months). Haas et al. [11] retrospectively analysed the short-term clinical course of 14 patients who had mechanical valves implanted in the pulmonary position. Of these patients, 7 had a PVR late after TOF repair. During a mean follow-up time of mean 35 ± 22 months, there was no mortality, valve thrombosis or haemolytic anaemia. Goor et al. [12] conducted a retrospective study of 7 patients who underwent isolated mechanical valve PVR. This small case series demonstrated that mechanical valves were a safe option from a thromboembolic risk point of view. Reintervention rates were, however, high during the follow-up period.

CLINICAL BOTTOM LINE We conclude from the best evidence available that mechanical prosthetic valves do play a role in patients who require PVR late after repair of TOF. With adequate anticoagulation, they represent a safe alternative to biological valves. Although the literature is very limited, in terms of patient numbers, many of the papers demonstrate an acceptable early mortality rate [3, 5–9, 11, 12]. There is significant variability in the regimes of anticoagulation in these patients, and the overall reported rate of valvar thrombosis, thromboembolic events and major haemorrhagic complications has also been variable. The overall rate of valvar thrombosis and other thromboembolic events is promising [2–12]. One paper concluded that there was a higher rate of thrombosed valves [6]. Thrombotic events were often attributed to poor adherence to the anticoagulation regime. Conversely, three papers recorded no thromboembolic events during the follow-up period [7, 11, 12]. In patients with residual pulmonary arterial stenoses, who may require further intervention on this, it may be less prudent to use mechanical valves as it precludes any percutaneous approach in dealing with this. Longer term outcomes in any tetralogy patient is also dependent on many other factors not taken into account in this paper and include age at primary repair, type of initial repair, ventricular dysfunction, timing of PVR and many other factors. Outcome analyses will always have to be done with these in mind. Three papers recorded major haemorrhagic events during their follow-up period and concluded that these were a rare outcome [4, 5, 8]. When appropriate anticoagulation is adhered to, mechanical pulmonary prostheses appear to be relatively safe in patients late after repair of TOF. We have also found that the rationale for insertion of mechanical valves in the pulmonary position late after TOF repair varies across centres is still controversial. Furthermore, their use in patients with concomitant pulmonary arterial stenoses may be less advisable as this will prevent future percutaneous interventions of the pulmonary arterial tree. More research is required to accurately compare the haemodynamic properties of mechanical valves in the pulmonary position compared with other valves. Additionally, a more consistent follow-up of these patients in terms of echocardiographic, valve-related and warfarin-related complications is needed. With this information, clearer conclusions may be drawn when considering their role.

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Table 1: Best evidence papers Author, date and country Study type (level of evidence

Patient group

Outcomes

Key results

Comments

Horer et al. (2009), Ann Thorac Surg, Germany [2]

Retrospective data from 19 patients who underwent pulmonary valve replacement surgery with a mechanical valve were matched by age, sex and follow-up time with 19 patients who had a biological valve

Valve thrombosis

1 (7.7%)

Reintervention

1 (7.7%)

Haemodynamic properties of mechanical valves are initially superior to biological valves; however, they decline faster Reintervention rates were acceptable The authors state that mechanical valves should be considered in the pulmonary position if they already have another mechanical valve or they are anticoagulated due to rhythm disturbance

13 of these patients had PVR late after TOF repair Mean follow-up time was 5.8 ± 2.6 years

This study was limited by the small sample size and the retrospective analysis Shin et al. (2012), Ann Thorac Surg, Korea [3] Cohort study (level 2b)

37 patients who underwent 38 mechanical pulmonary valve replacements were retrospectively reviewed The median age of the patients was 13.5 years (7 months to 23 years) The median follow-up duration was 24.6 months (1.3 months to 22.5 years)

Stulak et al. (2010), Ann Thorac Surg, USA [4] Cohort study (level 2b)

This is a single-centre retrospective study over a period of 40 years. 54 patients had a mechanical prosthesis pulmonary valve replacement 40 of 52 patients were operated on after 2004 Bleeding complications were compared with a 1:2-matched patient cohort receiving a bioprosthetic PVR

Perioperative mortality

0 (0%)

Mortality

10 year: 1 (3%) (excluding 1 patient who died in a traffic accident)

Freedom from thromboembolism or other bleeding event Freedom from reoperation rate

1 year: (92%) 5 years: (92%) 10 years: (78.8%) 1 year: 100 (100%) 5 years: 100 (100%) 10 years: 36 (85.7%)

Overall survival

81%

Freedom from perivalvar leak, vegetations, pannus formation or valve thrombosis at last follow-up

45 (88.2%)

Freedom from reoperation 5/10 years

5 years: 100% 10 years: 100%

Severe bleeding complications

3 (5.6%)

Cohort study (level 2b)

In this paper, 22 consecutive patients underwent a total of 25 pulmonary valve replacements with mechanical prosthesis The mean age was 32 ± 11 years (14–50 years) Mean follow-up 7.6 ± 7.6 years (0.29–24 years)

The authors recommend a mechanical valve in patients who have undergone prior sternotomies and in patients who are actively growing Limitations include small sample size and that it is a retrospective study Mechanical PVR provides excellent durability Bleeding risk is very low with therapeutic INR and having a tissue PVR does not reduced the risk of bleeding

Median follow-up of the early survivors was 2.2 years (3 months to 20 years) Dos et al. (2011), Int J Cardiol, Spain [5]

Durability of mechanical valve in the pulmonary position was excellent. Bleeding and thromboembolic events due to anticoagulation were rare

Mechanical PVR should be considered where there have been multiple operations or they are anticoagulated for another reason Limitations include the small sample size and the retrospective analysis

Postoperative mortality

1 (4%)

Major bleeding episode

0 (0%)

Valve thrombosis and reoperation

3 (12%)

Mechanical valves may be an alternative to tissue valves Correct anticoagulation is very important for the reduction of the risk of thrombosis The data suggested that severe RV dysfunction and CCF are risk factors for valve thrombosis

Continued

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Cohort study (level 2b)

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Table 1: (Continued) Author, date and country Study type (level of evidence

Patient group

Outcomes

Key results

Comments

Limitations included a very small sample size and retrospective analysis Tokunaga et al. (2008), J Artif Organs, Japan [6] Cohort study (level 2b)

Study to investigate isolated pulmonary valve replacement using xenobioprostheses and mechanical valves 24 cases were reviewed, 18 bioprostheses and 6 mechanical valves

Operative mortality

0 (0%)

Valve thrombosis

2 (33.3%)

Valve-related event-free survival at 15 years

66.7%

Isolated pulmonary valve replacement can be done with both mechanical and biological valves adequately There is a higher rate of thrombosis in mechanical valve with no statistically significant difference between event-free survival Limitations include small sample size and retrospective analysis

Waterbolk et al. (2006), Eur J Cardiothoracic Surg, Netherlands [7] Cohort study (level 2b)

Study of 28 PVRs with mechanical valves. The results and follow-up were reviewed retrospectively where death and reoperation were end points Follow-up was by routine transthoracic echocardiogram

Thirty-day hospital mortality

1 (3.6%)

Freedom from reoperation

1 year: 100% 10 years: 100%

Thromboembolic events

0 (0%)

This series refutes the bad reputation that mechanical valves in the pulmonary position have. They have a much lower than expected rate of reoperation and no thromboembolic events were noted Limitations include a small sample size and the retrospective single-centre analysis

Ovcina et al. (2011), Interact CardioVasc Thorac Surg, Austria [8] Cohort study (level 2b)

A total of 24 PVRs were done between April 2004 and December 2009

Perioperative and mid-term mortality

0 (0%) All patients alive and well today

All patients had previously had a mean of 2.26 sternotomies and had been diagnosed with pure or predominant PR after their previous intervention

Postoperative bleeding requiring resternotomy

2 (8%)

Thrombotic event

1 (4%)

Valve malfunction, failure, tissue growth within the structure at final follow-up

0 (0%)

In our series of 24 patients (mean age, 23.1 ± 6.6 years; range 16–36 years)

Mechanical valve prostheses in the pulmonary position have promising short- and mid-term results The authors attribute the negative view of mechanical valves in the RVOT to the lack of large patient series Limitations include small sample size and limited follow-up duration

The mean follow-up time being 31.9 ± 15.9 months (range 6.9– 67.1 months) Deorsola et al. (2010), Ann Thorac Surg, Italy [9]

4 patients who had PVR with a mechanical valve after TOF repair have been included in this study

Operative mortality

0 (0%)

Thrombotic events

0 (0%)

Cohort study (level 2b)

Mean follow-up time was 11 years

NYHA functional class 1 after surgery

4 (100%)

Mean age was 17 years

Rhythm disturbance during follow-up

0 (0%)

Valve thrombosis in the tetralogy of Fallot patients

3 (9.1%)

Reiss et al. (2005), ASAO J, Germany [10]

This study was designed to evaluate the efficacy and complications of using anticoagulation in congenital heart disease patients who

This study shows good midand long-term results. The authors suggest that the mechanical valve is a good option providing good adherence to long-term anticoagulation is present Limitations include a small sample size The use of mechanical valves in congenital heart disease patients is effective and safe. There is a greater risk of valve thrombosis in the right-sided

Continued

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J.R. Abbas and J.A. Hoschtitzky / Interactive CardioVascular and Thoracic Surgery

Table 1: (Continued) Author, date and country Study type (level of evidence

Patient group

Outcomes

Key results

Comments

Cohort study (level 2b)

required a mechanical prosthesis

valves compared with the left

Pathologies included, tetralogy of Fallot (n = 33), morbus Ebstein (n = 4), atrioventricular canal (n = 13), truncus arteriosus communis (n = 5), transposition of the great arteries (n = 10) and congenitally corrected transposition of the great arteries (n = 3)

Limitations include small samples size

Haas et al. (2005), Ann Thorac Surg, Germany [11] Cohort study (level 2b)

From November 1998 until November 2003, 14 patients underwent PVR with mechanical valved conduit Of the 14 patients, 7 were tetralogy of Fallot, pulmonary atresia with ventricular septal defect in 3, common arterial trunk in 3 and severe subaortic stenosis with subsequent Ross procedure in 1 patient

Mortality

In hospital: 0 (0%) During follow-up: 0 (0%)

Operative complication

Bleeding (within 5 days): 3 (21.4%)

Thromboembolic complications during follow-up

0 (0%)

Haemolytic anaemia during follow-up

0 (0%)

Mortality

0 (0%)

Operative complications

Early: 0 (0%) Late: 0 (0%)

Reintervention

4 (57.1)

Thromboembolic events

0 (0%)

Implantation of a mechanical valve in the pulmonary area may provide a lifelong alternative to xenografts and homografts. This will therefore reduce the morbidity and mortality associated with reoperation Limitations include the small sample size

Mean age at operation was 24.8 ± 9.2 years (tetralogy 10–38 years). All patients had a mean of 3.0 ± 1.2 previous operations by means of a median sternotomy (range 2–5) Follow-up time ranged from 11 to 63 months (mean 35 ± 22 months) Goor et al. (1984), J Thorac Cardiovasc Surg, Israel [12] Cohort study (level 2b)

7 patients underwent mechanical valve implantation in a 3-year period Valves used were isolated mechanical valves and those constructed into valved conduits

REFERENCES [1] Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS. Interact CardioVasc Thorac Surg 2003;2:405–9. [2] Horer J, Vogt M, Stierle U, Cleuziou J, Prodan Z, Schreiber C. A comparative study of mechanical and homograft prosthesis in the pulmonary position. Ann Thorac Surg 2009;88:1534–9. [3] Shin HJ, Kim YH, Ko JK, Park IS, Seo DM. Outcomes of mechanical valves in the pulmonic position in patients with congenital heart disease over a 20-year period. Ann Thorac Surg 2012;95: 1367–71. [4] Stulak JM, Dearani JA, Burkhart HM, Connolly HM, Warnes CA, Suri RM et al. The increasing use of mechanical pulmonary valve

[5]

[6]

[7]

[8]

In this small series, while reintervention rate was significant, the authors observed a very low rate of complication, operative mortality and thromboembolic phenomena

replacement over a 40-year period. Ann Thorac Surg 2010;90: 2009–14. Dos L, Munoz-Guijosa C, Mendez AB, Ginel A, Montiel J, Padro JM et al. Long term outcome of mechanical valve prosthesis in the pulmonary position. Int J Cardiol 2012;150:173–6. Tokunaga S, Masuda M, Shiose A, Tomita Y, Morita S, Tominaga R. Isolated pulmonary valve replacement: analysis of 27 years of experience. J Artf Organs 2008;11:130–3. Waterbolk TW, Hoendermis ES, den Hamer IJ, Ebels T. Pulmonary valve replacement with a mechanical prosthesis. Promising results of 28 procedures in patients with congenital heart disease. Eur J Cardiothoracic Surg 2006;30:28–32. Ovcina I, Knez I, Curcic P, Ozkan S, Nagel B, Sorantin E et al. Pulmonary valve replacement with mechanical prostheses in re-do Fallot patients. Interact CardioVasc Thorac Surg 2011;12:987–91.

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Mean follow-up time was 72 months (range 6–132 months)

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[9] Deorsola L, Abbruzzese PA, Aidala E, Cascarano MT, Longo S, Valori A et al. Pulmonary valve replacement with mechanical prosthesis: long-term results in 4 patients. Ann Thorac Surg 2010;89:2036–8. [10] Reiss N, Blanz U, Bairaktaris H, Koertke A, Körfer R. Mechanical valve replacement in congenital heart defects in the era of international normalized ratio self-management. ASAIO J 2005;51:530–2.

[11] Haas F, Schreiber C, Hörer J, Kostolny M, Holper K, Lange R. Is There a role for mechanical valved conduits in the pulmonary position? Ann Thorac Surg 2005;79:1662–7. [12] Goor DA, Hoa TQ, Mohr R, Smolinsky A, Hegesh J, Neufeld HN. Pericardialmechanical valved conduits in the management of right ventricular outflow tracts. Preliminary report. J Thorac Cardiovasc Surg 1984;87:236–43.

Is there a role for mechanical valve prostheses in pulmonary valve replacement late after tetralogy of Fallot repair?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: What is the role of mechanical va...
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