Echocardiographic evaluation of patients undergoing mitral valve replacement with crossed papillopexy

Abstracts

BACKGROUND: Techniques for mitral valve replacement with preservation of the subvalvular apparatus have proven their superiority, and crossed papillopexy is a new technical option which, besides allowing Preservation of the anatomical structures, provides contractility support and protection to the myocardium during ventricular diastole. The technique requires further studies that document its results. OBJECTIVE: To evaluate the left atrial and ventricular function by Doppler echocardiography in patients who have undergone mitral valve replacement with crossed papillopexy. METHODS: Fifteen patients underwent mitral valve replacement, 9 (60%) of them male, and the mean age was 45.7 years. As to the etiology of aortic valve disease, nine (60%) cases were degenerative, three (20%) were rheumatic, two (13.3%) were ischemic, and one patient (6.7%) had infectious endocarditis. After closure of the atriotomy and anatomical evaluation of the valvar apparatus, the anterior leaflet was detached from the annulus and centrally split in halves, each one with its complex tendinous chords attached to the opposing commissure by its medial extremity. Biological (13 cases) or mechanical prosthetic valves were implanted and secured with separate stitches. Reduction of the valvar annulus was performed in patients with dilated cardiomyopathy. Patients underwent clinical and Doppler echocardiographic examinations before surgery and six months after the procedure. RESULTS: All patients were clinically stable at discharge. A significant reduction in ventricular and atrial diameters was demonstrated (p< 0.001) without impairment of the entry and exit points of the left ventricle. CONCLUSION: Mitral valve replacements performed with the crossed papillopexy technique showed favorable results with a positive effect on the recovery of left atrial and ventricular morphology.

Mitral valve insufficiency; cardiomyopathy dilated; papillary muscles

FUNDAMENTO: As técnicas de substituição mitral com preservação do aparelho subvalvar têm reafirmado sua superioridade, sendo a papilopexia cruzada uma nova opção técnica que além de permitir preservação de estruturas anatômicas, oferece suporte na contração e protege o miocárdio na diástole ventricular, necessitando de estudos que documentem seus resultados. OBJETIVO: Avaliar as funções atrial e ventricular esquerdas, através de ecodopplercardiografia, em pacientes submetidos à substituição da valva mitral com papilopexia cruzada. MÉTODOS: Foram submetidos à substituição valvar mitral 15 pacientes, sendo nove (60%) do sexo masculino, com idade média de 45,7 anos. Quanto à etiologia, nove (60%) casos eram degenerativos, três (20%) reumáticos, dois (13,3%) isquêmicos e um (6,7%) com endocardite infecciosa. Após atriotomia e avaliação anatômica do aparelho valvar o folheto anterior foi desinserido do anel e centralmente dividido, sendo cada metade com seu complexo de cordas tendíneas fixada à comissura oposta por sua extremidade medial. Foi Implantada a prótese valvar biológica (em 13 casos) ou mecânica, fixada por pontos separados, com redução do anel valvar nos casos com miocardiopatia dilatada. Foram tomadas avaliações clinicas e ecodopplercardiográficas no pré-operatório, e sexto mês de pós-operatório. RESULTADOS: Todos os pacientes receberam alta em condições clínicas estáveis. Foi demonstrada redução significativa dos diâmetros ventriculares e dos diâmetros atriais (p< 0,001) sem comprometimento das vias de entrada e saída do ventrículo esquerdo. CONCLUSÃO: As substituições da valva mitral realizadas com a técnica de papilopexia cruzada apresentaram resultados favoráveis, com efeito positivo na recuperação morfológica atrial e ventricular esquerdas.

Insuficiência da valva mitral; cardiomiopatia; dilatada; músculos papilares

FUNDAMENTO: Las técnicas de sustitución mitral con preservación del aparato subvalvular han estado reafirmando su superioridad, siendo la resuspensión de los músculos papilares una nueva opción técnica que además de permitir la preservación de estructuras anatómicas, ofrecer soporte en la contracción y protege el miocardio en la diástole ventricular, necesitando estudios que documenten sus resultados. OBJETIVO: Evaluar las funciones atrial y ventricular izquierdas, mediante ecocardiografía Doppler, en pacientes sometidos a sustitución de la válvula mitral con resuspensión de los músculos papilares. MÉTODOS: Se sometieron a sustitución valvular mitral 15 pacientes, siendo nueve (60%) del sexo masculino, con una edad promedio de 45,7 años. En cuanto a la etiología, nueve (60%) casos eran degenerativos, tres (20%) reumáticos, dos (13,3%) isquémicos y uno (6,7%) con endocarditis infecciosa. Después de la atriotomía y evaluación anatómica del aparato valvular, el velo anterior se retiró del anillo y se dividió centralmente, siendo cada mitad con su complejo de cuerdas tendinosas fijadas a la comisura opuesta por su extremidad medial. Se implantó prótesis valvular biológica (en 13 casos) o mecánica, fijada por puntos separados, con reducción del anillo valvular en los casos con miocardiopatía dilatada. Se realizaron evaluaciones clínicas y por ecocardiografía Doppler en el preoperatorio, y sexto mes de postoperatorio. RESULTADOS: Todos los pacientes recibieron alta en condiciones clínicas estables. Se demostró reducción significativa de los diámetros ventriculares y de los diámetros atriales (p< 0,001) sin compromiso de las vías de entrada y salida del ventrículo izquierdo. CONCLUSIÓN: Las sustituciones de la válvula mitral realizadas con la técnica de resuspensión de los músculos papilares presentaron resultados favorables, con efecto positivo en la recuperación morfológica atrial y ventricular izquierdas.

Insuficiencia de la válvula mitral; miocardiopatía dilatada; músculos papilares

ORIGINAL ARTICLE

Echocardiographic evaluation of patients undergoing mitral valve replacement with crossed papillopexy

Geraldo Paulino Santana Filho; Otoni Moreira Gomes; Gilson José de Oliveira; Débora Rodrigues; Ana Cláudia Nogueira; Rômulo Sales; Delzirene Botelho; Pinheiro; Antonio Calzada Machado; Nivaldo Gomes Oliveira

Santa Casa de Misericórdia de Goiânia, Goiânia, GO - Brazil

Mailing address

SUMMARY

BACKGROUND: Techniques for mitral valve replacement with preservation of the subvalvular apparatus have proven their superiority, and crossed papillopexy is a new technical option which, besides allowing preservation of the anatomical structures, provides contractility support and protection to the myocardium during ventricular diastole. The technique requires further studies that document its results.

OBJECTIVES: To evaluate the left atrial and ventricular function by Doppler echocardiography in patients who have undergone mitral valve replacement with crossed papillopexy.

METHODS: Fifteen patients underwent mitral valve replacement, 9 (60%) of them male, and the mean age was 45.7 years. As to the etiology of aortic valve disease, nine (60%) cases were degenerative, three (20%) were rheumatic, two (13.3%) were ischemic, and one patient (6.7%) had infectious endocarditis. After closure of the atriotomy and anatomical evaluation of the valvar apparatus, the anterior leaflet was detached from the annulus and centrally split in halves, each one with its complex tendinous chords attached to the opposing commissure by its medial extremity. Biological (13 cases) or mechanical prosthetic valves were implanted and secured with separate stitches. Reduction of the valvar annulus was performed in patients with dilated cardiomyopathy. Patients underwent clinical and Doppler echocardiographic examinations before surgery and six months after the procedure.

RESULTS: All patients were clinically stable at discharge. A significant reduction in ventricular and atrial diameters was demonstrated (p< 0.001) without impairment of the entry and exit points of the left ventricle.

CONCLUSION: Mitral valve replacements performed with the crossed papillopexy technique showed favorable results with a positive effect on the recovery of left atrial and ventricular morphology.

Key words: Mitral valve insufficiency/surgery; cardiomyopathy, dilated; papillary muscles/surgery.

Introduction

There is evidence of the advantages of valvoplasty over prosthetic valve replacement for the treatment of mitral valve insufficiency¹. However, indications for surgery in patients with advanced mitral valve degeneration, requiring replacement with artificial valves, are still relatively frequent. The concept of not excising all chordal and papillary muscles has been established and divulged; now, new discussions focus on defining technical options for better use of the advantages of maintaining papillary muscle-annular continuity. Recent publications have agreed on the preservation of both leaflets^2,3, so as to not interfere with the function of the prosthesis; echocardiography is an efficient method for performing this evaluation⁴.

Moreover, evidence has also accumulated of the benefits of valve replacement using ventricular remodeling techniques in treating advanced heart failure with significant mitral functional insufficiency^5,6, since exclusive interventions on the annulus are subjected to the recurrence of mitral insufficiency secondary to the progression of myocardial degeneration.

Based on previously described procedures of the subvalvar approach, Gomes et al.⁷ introduced the crossed papillopexy⁸ method in an attempt to optimize ventricular performance following mitral valve replacement, reestablishing ventricular geometry even in hearts with significant dilation. The aim of this study is to describe the progression of left atrial and ventricular function according to echocardiographic parameters in the sixth postoperative month of patients who underwent mitral valve replacement with the crossed papillopexy technique.

Method

This is a prospective study of 15 patients who consecutively underwent mitral valve replacement with crossed papillopexy at the Serviço de Cirurgia Cardiovascular da Santa Casa de Misericórdia de Goiânia.

The study was approved by the institution's Research Ethics Committee (CONEP register number 12507), and was conducted after the formal informed consent of the patients.

Nine (60%) patients were men and 6 (40%) were women. Patients' ages ranged from 17 to 69 years (49.9 ± 10.2).

Inclusion criterion was the presence of severe mitral insufficiency (defined as a regurgitation flow >40%) with atrial e ventricular repercussions. The most frequent cause of valvar dysfunction was fibroelastic degeneration in nine cases (60.0%), rheumatic valvar lesion in three (20.0%), ischemic mitral insufficiency in two (13.3%), and valvar degeneration secondary to endocarditis in one case (6.7%) (Table 1).

All patients were receiving clinical treatment, although without an adequate response, and all were operated on by the same surgical team.

Clinical and Doppler echocardiographic evaluation was performed before surgery and in the first, third, and sixth months after surgery; the aim of this study was the comparison between pre- and postoperative evaluations (at sixth months).

The functional grade of heart failure was determined according to the Criteria Committee of The New York Heart Association⁹.

Doppler echocardiograms were performed by the same professional using the HDI 5000 device with P4-2 MHz transducer (Philips, Einthoven - Holland). The left ventricular ejection fraction was calculated as per the volumes obtained using the Teichholz formula. There were seven cases (46.7%) of ruptured tendinous chordae in the posterior mitral leaflet and one case in the anterior leaflet (6.7%). The preoperative left ventricular function was preserved in ten cases (66.6%) and impaired in five cases (33.4%). In the postoperative evaluation, transprosthetic and aortic gradients were assessed to detect potential obstructions.

Operative technique

All surgeries were performed by standard median sternotomy with cannulation of the ascending aorta and of both caval veins separately, after systemic heparinization and mild hypothermia (32ºC). Antegrade blood cardioplegia was used to protect the myocardium from damage.

The mitral valve was exposed through left atriotomy with an incision parallel to the interatrial sulcus. The need for valve replacement was confirmed after direct inspection and analysis as to the presence of leaflet calcification, fusion, fibrosis, or prolapse, chordal rupture, fibrosis, or elongation, and annular dilation.

The anterior leaflet was lifted with two repair stitches on its free edge, and its subvalvar apparatus was carefully inspected. Depending on A circular incision was made at the base of the anterior leaflet approximately two millimeters away from the mitral annulus and extending slightly below the commissural points. The anterior leaflet was centrally divided and each half, with its chordae tendineae complex, was attached to the opposite commissure by its medial extremity (Figure 1).

The use of valvar prostheses with diameters smaller than the native annulus helped reduce the size of the base of the heart. The sutures were then passed through the prosthetic ring and sutured to the valvar annulus. Biological prostheses (Labcor - Belo Horizonte - MG) and mechanical prostheses (CarboMedics - Austin -Texas - USA) were used, as per the indication for each case. With the patient's heart beating, the prosthesis was carefully examined to check for perfect function. Associated procedures were indicated for seven patients (Table 1).

After the end of the surgery, patients who were hemodynamically stable were transferred to the intensive care unit where they remained under continuous monitoring.

All patients were followed during hospitalization and as outpatients according to the protocol for obtaining and comparing data.

Statistical analysis of the paired data obtained involving normal distribution variables was performed with Student's t test.

Results

No deaths occurred in hospital or during the six-month follow-up. Four patients (26.6%) had a diagnosis of mild aortic insufficiency, which persisted during the follow-up period. There were no hemorrhagic or infectious complications.

Mean end-diastolic ventricular diameters were reduced from 65.3 ± 8.7 mm to 51.5 ± 8.9 mm (p<0.001), whereas the end-systolic diameters were reduced from 44.3 ± 9.1 mm to 35.2 ± 1.1 mm (p<0.001). Atrial diameters varied favorably from 55.1 ± 8.6 mm to 45.3 ± 8.9 mm (p< 0.001). The end-diastolic volume was reduced from 229.7 ± 85.0 ml to 130.5 ± 51.7 ml (p<0.001), and the end systolic volume from 91.6 ± 64.2 ml to 58.7 ± 50.3 ml (p = 0.001). The systolic volume decreased from 138.0 ± 41.0 ml to 78.5 ± 30.8 ml (p = 0.002). The percentage of systolic shortening ranged from 32.1 ± 9.4 % to 32.2 ± 8.7% (p=0.917), and the ejection fraction had a slight drop compared to preoperative levels, from 62.9 ± 14.0 % to 61.9 ± 11.7 % (p=0.684) (Figure 2).

Cardiac mass was reduced from 294.9 ± 115.5 g to 214.9 ± 64.4 g (p= 0.001). Pulmonary artery pressure improved significantly, decreasing from 53.4 ± 13.1 mmHg to 32.9 ± 7.9 mmHg (p< 0.001). (Table 2).

The mean transprosthetic gradient was 3.9 ± 1.3 mmHg, and no impairment was observed in the entry pathways and the aortic subvalvar region of the left ventricle. All patients experienced significant clinical improvement. Six (40.0%) patients were in NYHA IV functional class, eight (53.3%) in functional class III, and one (6.7%) in class II. After the six-month follow-up, two patients (13.3 %) are in functional class II and 13 (86.7%) are in functional class I.

Discussion

Several techniques for subvalvar preservation have been published confirming improvement in ventricular performance, including cases of severely impaired systolic function^10-12.

Only a few studies do not report benefits from preservation of the tendinous chordae^13,14.

Echocardiographic evaluation is considered an adequate method to provide information about the geometry and functional status of the heart after mitral valve replacement; moreover, the noninvasive nature of the method in assessing myocardial performance is a favorable aspect¹⁵.

In this study, changes in left ventricular morphology translated into a significant reduction of ventricular diameters. Papillary muscle traction prevents passive diastolic dilation, and the loss of this restraining force is reflected in the ventricular wall, since annulus-papillary muscle continuity regulates ventricular preload, thus determining the contraction force¹⁶. A reduction in ventricular wall shortening and dyskinesia was observed in the zone underlying the base of the papillary muscles during the postoperative period of valve replacement by standard technique; this directly reflects the impairment caused by the lack of tension of the papillary muscle to the ventricular wall¹⁷.

Recovery of the shortening percentage has been described for hearts with a preserved subvalvar apparatus¹⁸, which, associated with the behavior of the torsional deformation, reflects cardiomyocyte contractility¹⁹. In this study, the evaluation of the systolic shortening percentage showed a slight improvement. Although not significant, these results can be considered satisfactory in face of the short six-month follow-up.

Reduction of cardiac mass reflects positive left ventricular remodeling, and a 27.1% (p = 0.001) reduction in hypertrophy was observed using left ventricular mass variation analysis.

On the other hand, myocardial dysfunction in patients with mitral insufficiency is generally disguised because part of the ventricular ejection is discharged into a low-pressure and low-resistance chamber, the left atrium. Therefore, the ejection fraction of patients with mitral insufficiency in the preoperative phase can be overestimated²⁰. This detail accounts for a 1.6% (p=0.684) reduction in the ejection fraction after six months of follow-up in this study, despite the improvement in the clinical conditions and ejection volume, findings which have been described in other studies as well¹⁶. Moreover, elimination of mitral valve regurgitation leads to an immediate increase in post-load, and the non-adapted left ventricle starts to eject blood against systemic resistance, which has been considered an important cause of deterioration of the ventricular function in the postoperative phase of patients with mitral insufficiency. On the other hand, ventricular impairment is less marked in mitral valvuloplasties, which shows that the increase in post-load is not self-explanatory. It is believed, therefore, that the preservation of the subvalvar apparatus in mitral repair is fundamental to achieve the best results.

Such evidence thus justifies the efforts in research to enhance the correlated operative techniques.

The feasibility of crossed papillopexy can also be confirmed for not having generated restriction of the implanted prosthetic leaflets and for not having caused obstruction in the left ventricular entry pathway, which is also reflected in the recovery of the pulmonary artery systolic pressure and in left atrial remodeling. A significant reduction was observed in the left atrial diameters (p< 0.001) and in the pulmonary artery systolic pressure of 38.5%. Left atrial remodeling can be considered a prognostic factor of clinical improvement and survival after valve replacement surgery²¹.

In the presence of aortic valve regurgitation, which was the case in 26.6% of this group of patients, the benefit of employing the technique has been confirmed. In these cases, there was no progression of ventricular dysfunction, a pathological condition in which the potential of dilation and harmful diastolic remodeling is much greater.

In excessively dilated hearts, with increased interpapillary distance and its higher repositioning in ventricular cavity, the support provided by papillary muscles to longitudinal shortening is limited.

In the valve replacement technique originally described by MIKI et al²², the papillary muscles become parallel to the ventricular wall, thus favoring wider displacement of the wall and undesirable sphericity. Crossed papillopexy, with the implantation of each half of the leaflet in the opposing commissure, has the objective of increasing the tension of the papillary muscles acting more intensely in reverse left ventricular remodeling. Perhaps the benefits may be even more marked in cases of dilated myocardiopathy, aimed at making the papillary muscles participate in ventricular contraction again. The technique employed in this study, which corrects mitral insufficiency, tends to promote internal remodeling of the ventricular cavity and reduce the diameter at the base of the heart, thus reducing mitral annulus circumference through the implantation of a prosthesis one or two sizes smaller than the left atrioventricular annulus.

Conclusion

Taking into consideration that this is non-randomized, non-comparative, small-sized sample study with only six months of follow-up, crossed papillopexy is a feasible technical alternative for promoting geometric recovery of the left cardiac chambers.

Acknowledgements

We wish to thank the Department of Cardiology of the Santa Casa de Misericórdia de Goiânia: Ana Claudia Nogueira, Delzirene Pinheiro Botelho, Rômulo Sales, Luiz Rassi Júnior, and Antônio Calzada Machado, for their continuous and valuable support.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Sources of Funding

There were no external funding sources for this study.

Study Association

This article is part of the thesis of master submitted by Geraldo Paulino Santana Filho, from Núcleo de pós-graduação e pesquisa da Fundação Cardiovascular São Francisco de Assis - Servcor.

References

• 1. Akins CW, Hilgenberg AD, Buckley MJ, Vlahakes GJ, Torchiana DF, Daggett VM, et al. Mitral valve reconstruction versus replacement for degenerative or ischemic mitral regurgitation. Ann Thorac Surg. 1994; 58 (3): 668-75.
• 2. Hennein HA, Swain JA, McIntosh CL, Bonow RO, Stone CD, Clark RE. Comparative assessment of chordal preservation versus chordal resection during mitral valve replacement. J Thorac Cardiovasc Surg. 1990; 99: 828-37.
• 3. Yun KL, Sintek CF, Miller C, Pfeffer TA, Kochamba GS, Khonsari S, et al. Randomized trial comparing partial versus complete chordal-sparing mitral valve replacement: effects on the left ventricular volume and function. J Thorac Cardiovasc Surg. 2002; 123: 707-14.
• 4. Leal JC, Gregori F Jr, Galina LE, Thevenard R, Braile DM. Avaliação ecocardiográfica em pacientes submetidos à substituição de cordas tendíneas rotas. Rev Bras Cir Cardiovasc. 2007; 22 (2): 184-91.
• 5. Buffolo E, Paula IM, Branco JNR, Carvalho ACC, MantovanI C, Caputi G. Tratamento da insuficiência cardíaca terminal através da correção da insuficiência mitral secundária e remodelação ventricular. Rev Bras Cir Cardiovasc. 2001; 16 (3): 203-11.
• 6. Gaiotto FA, Puig LB, Mady C, Fernandes F, Tossuniam CE, Pardi MM, et al. Substituição da valva mitral com tração dos músculos papilares em pacientes com miocardiopatia dilatada. Rev Bras Cir Cardiovasc. 2007; 22 (1): 68-74.
• 7. Gomes OM. Papilopexia para preservação da degeneração miocárdica após substituição mitral. Arq Bras Cardiol. 1987; 49 (supl. 1): 165-9.
• 8. Gomes OM, Gomes ES, Santana Fş GP, Pontes JCDV, Benfatti RA. Nova abordagem técnica para papilopexia cruzada em operação de substituição valvar mitral: resultados imediatos. Rev Bras Cir Cardiovasc. 2005; 20 (3): 340-5.
• 9. The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. 9th ed. Boston (Mass): Little, Brown & Co; 1994. p. 253-6.
• 10. David TE, Uden DE, Strauss HD. The importance of mitral apparatus in the left ventricular function after correction of mitral regurgitation. Circulation. 1983; 68 (Suppl 2): S76-82.
• 11. Hetzer R, Bougioukas G, Franz M, Borst HG. Mitral valve replacement with preservation of papillary muscles and chordae tendinae: revival of a seemingly forgotten concept. I. Preliminary clinical report. Thorac Cardiovasc Surg. 1983; 31 (5): 291-6.
• 12. Okita Y, Miki S, Ueda Y, Tahata T, SakaI T. Left ventricular function after mitral valve replacement with or without chordal preservation. J Heart Valve Dis. 1995; 4 (Suppl. 2): S181.
• 13. Rastelli GC, Tsakiris AG, Frye RL, Kirklin J. Exercise tolerance and hemodynamic studies after replacement of canine mitral valve with and without preservation of chordae tendinae. Circulation. 1967; 35 (Suppl. 4): S34-S41.
• 14. Björk VO, Björk L, Malers E. Left ventricular function after resection of the papillary muscles in patients with total mitral valve replacement. J Thorac Cardiovasc Surg. 1964; 48 (4): 635-9.
• 15. Deutsch HJ, Curtis JM, Bongarth C, Behlke E, Boroski A, Vivie ER. Left ventricular geometry and function before and after mitral valve replacement. J Heart Valve Dis. 1994; 3: 288-94.
• 16. Goldman ME, Mora F, Guarino T, Fuster V, Mindich BP. Mitral valvuloplasty is superior to valve replacement for preservation of left ventricular function: an intraoperative two-dimensional echocardiographic study. J Am Coll Cardiol. 1987; 10: 568-75.
• 17. Pitarys CJ II, Forman MB, Panayiotou H, Hansen DE. Long term effects of excision of the mitral valve apparatus on global and regional ventricular function in humans. J Am Coll Cardiol. 1990; 15: 557-63.
• 18. Izumi C, Himura Y, Iga K, Gen K, Komeda M, Ueda Y. Relationship between papillary muscle size and benefit to cardiac function in mitral valve replacement with chordal preservation. J Heart Valve Dis. 2001; 10: 57-64.
• 19. De Anda A, Komeda M, Nikolic SD, Daughters GT, Ingels NB, Miller C. Left ventricular function, twist and recoil after mitral valve replacement. Circulation. 1995; 92 (Suppl. 2): II458-II466.
• 20. Gomez-Doblas JJ, Schor J, Vignola P, Weinber D, Traad E, Carrilo R. Left ventricular geometry and operative mortality in patients undergoing mitral valve replacement. Clin Cardiol. 2001; 24: 717-22.
• 21. Reed D, Abbott RD, Smucker ML, Kaul S. Prediction of outcome after mitral valve replacement in patients with symptomatic chronic mitral regurgitation: the importance of left atrial size. Circulation. 1991; 84: 23-34.
• 22. Miki S, Kusuhara K, Ueda Y, Komeda M, Okita Y, Tahata T. Mitral valve replacement witch preservation of chordae tendinae and papillary muscles. Ann Thorac Surg. 1988; 45: 28-32.

Publication Dates

• Publication in this collection
  13 Oct 2009
• Date of issue
  Aug 2009

History

• Accepted
  18 June 2008
• Reviewed
  08 May 2008
• Received
  04 Feb 2008