Menoufia Medical Journal

ORIGINAL ARTICLE
Year
: 2016  |  Volume : 29  |  Issue : 3  |  Page : 674--679

Evaluation of early outcomes after mitral replacement in rheumatic heart patients with pulmonary hypertension


Ahmed L Dokhan1, Mohamed E Abd El-Raouf2, Islam M Ibrahim1, Mohammed G Abdellatif1,  
1 Department of Cardiothoracic Surgery, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
2 Department of Cardiothoracic Surgery, Faculty of Medicine, Al-Azhar University, Cairo, Egypt

Correspondence Address:
Mohammed G Abdellatif
102 El-Baz Street, Qwesna, Menoufia, 32631
Egypt

Abstract

Objectives To evaluate and compare the  early hemodynamic results and echocardiographic data after rheumatic mitral valve replacement (MVR) in patients with mild and severe pulmonary hypertension (PH). Background Development of PH in association with valvular dysfunction is a marker of advanced disease. Some authors have reported no greater risk in patients with severe PH compared with those with a mild degree of PH, whereas others reported that severe PH is associated with a greater operative risk and a poorer long-term prognosis. It is desirable to reassess the outcome in these patients with newer anesthetic agents, improved valve prostheses, myocardial protection, and postoperative care. Patients and methods Between September 2013 and May 2015, this multicenter prospective observational study included 40 patients who presented with rheumatic mitral stenosis indicated for elective MVR divided into two equal groups: group A, with a mean pulmonary artery pressure (mPAP) equal to 26-40 mmHg, and group B, with mPAP more than 55 mmHg. All patients underwent conventional surgical MVR using cardiopulmonary bypass. Early hemodynamic improvement was observed with follow-up transthoracic echo performed 1 week and 3 months postoperatively Results Our study included 17 male and 23 female patients with a mean age of 32.40 years; all of them underwent conventional MVR with cardiopulmonary bypass. Throughout our study, we detected a statistically significant difference between both groups regarding the duration of postoperative mechanical ventilation and improvement in mPAP in both groups. There was a single case of morbidity in group B with no cases of mortality for 3 months postoperatively in both groups. Conclusion MVR is safe and effective even in patients with severe PH.



How to cite this article:
Dokhan AL, Abd El-Raouf ME, Ibrahim IM, Abdellatif MG. Evaluation of early outcomes after mitral replacement in rheumatic heart patients with pulmonary hypertension.Menoufia Med J 2016;29:674-679


How to cite this URL:
Dokhan AL, Abd El-Raouf ME, Ibrahim IM, Abdellatif MG. Evaluation of early outcomes after mitral replacement in rheumatic heart patients with pulmonary hypertension. Menoufia Med J [serial online] 2016 [cited 2020 Apr 5 ];29:674-679
Available from: http://www.mmj.eg.net/text.asp?2016/29/3/674/198753


Full Text

 Introduction



Although rheumatic valve disease was the predominant cause of mitral stenosis in the West, its prevalence has decreased in recent decades in sharp contrast to the developing world where chronic rheumatic disease remains the most common cause of both mitral regurgitation and stenosis [1] .

Development of pulmonary hypertension (PH) in patients with left heart disease is associated with a poor prognosis. Correction of valvular disease, either surgically or percutaneously, is at present the appropriate treatment [2] .

PH is a hemodynamic and pathophysiological condition defined as an increase in mean pulmonary arterial pressure (mPAP) more than or equal to 25 mmHg at rest as assessed by right heart catheterization [3] .

The updated clinical classification of PH in adults includes pulmonary arterial hypertension, PH due to left heart disease, PH due to lung disease, chronic thromboembolic PH, and miscellaneous forms [4] .

The mechanisms leading to PH in mitral stenosis are retrograde transmission of left heart pressures to the pulmonary venous and arterial beds (passive component), which triggers an increased vascular tone (vasoconstriction) in the pulmonary arterial bed (reactive component), and a subsequent pulmonary vascular remodeling, leading to irreversible pulmonary vascular disease [5] .

For diagnosis, Doppler echocardiography is the best tool for screening purposes. However, invasive measurements of pulmonary wedge pressure or left ventricular end-diastolic pressure may be necessary to confirm the diagnosis [6] .

Conflicting reports are available in the literature on the outcome of patients with PH after corrective surgery. Some authors have reported no greater risk in patients with severe PH, whereas others have reported that severe PH is associated with a greater operative risk, higher operative mortality, and a poorer long-term prognosis [7] .

Aim

The objective of our study was to evaluate and compare the early hemodynamic results and echocardiographic data after rheumatic mitral valve replacement (MVR) in patients with mild and severe PH.

 Patients and methods



After approval of the study proposal by the Menoufia Ethics Committee, this prospective observational study was conducted between September 2013 and May 2015 in two centers: Menoufia University Hospitals and Nasser Institute.

A total of 40 patients with rheumatic mitral valve stenosis who needed MVR were included in this study. Written informed consent was obtained from each patient before his or her enrollment in the trial. They were divided into two groups: group A, with a mPAP equal to 26-40 mmHg; and group B, with mPAP more than 55 mmHg. Patients with coronary artery disease, double-valve disease, emergency cases, redo cases, congestive heart failure, renal or hepatic dysfunction, and chronic obstructive airway disease were excluded from the study.

Each patient was subjected to full history taking, thorough clinical examination, preoperative laboratory and radiological investigations, and full transthoracic echocardiographic assessment including measurement of the left ventricular end-diastolic diameter (LVEDD), the left ventricular end-systolic diameter (LVESD), the left atrium size, the ejection fraction, the mitral valve area, the Wilkins score, and the pulmonary artery pressure.

All patients were operated under general anesthesia with a  Swan-Ganz catheter placed through a right internal jugular approach; conventional median sternotomy incision was carried out; cardiopulmonary bypass was instituted through aortobicaval cannulae. After antegrade cardioplegia, the mitral valve was exposed through paraseptal left atriotomy; the calcified leaflets were excised with chordal sparing as much as possible. The new mitral valve was implanted using interrupted nonabsorbable suture. Closure of the atriotomy, weaning from bypass, and closure of the sternotomy were carried out sequentially.

Patients were transferred intubated to the ICU with care focused on control of blood pressure; pulmonary artery pressure measurements were obtained during the first 24 h postoperatively using the Swan-Ganz catheter. When patients were hemodynamically stable, they were transferred to the ward, and an echocardiography was performed 1 week postoperatively. We followed patients in hospital until recovery of acceptable physical activity before being discharged home.

Follow-up was carried out in the outpatient clinic at 1 week, 1 month, and 3 months postoperatively, with transthoracic echocardiographic assessment at the 3-month visit.

All preoperative, operative, postoperative, and outpatient follow-up data were collected. Quantitative variables were expressed as mean and SD, whereas qualitative data were expressed as either number (n), ratio, or percentage according to relevance. Statistical significance was tested using an IBM compatible computer and IBM SPSS statistics (version 19; SPSS Inc., Chicago, Illinois, USA). Significance of quantitative variables was tested using a paired Student's t-test. We considered probability values less than 0.05 as statistically significant.

 Results



Demographic data and patients' comorbidities showed no significant difference between both groups ([Table 1]). There was a significant difference between both groups with regard to the preoperative NYHA classification ([Table 2]).{Table 1}{Table 2}

The operative data showed no significant difference between both groups ([Table 3]).{Table 3}

On comparing both groups regarding their mPAP at various stages of our study, we detected highly statistically significant differences at all stages of our study ([Table 4]).{Table 4}

On comparing both groups' arterial blood gases regarding their pH, PaCO 2 , and HCO 3 values at various stages of our study, we detected a statistically significant difference after extubation from mechanical ventilation.

There was a statistically significant difference between both groups regarding the duration of mechanical ventilation and the total hospital stay, although there was no significant difference regarding the duration of ICU stay ([Table 5]).{Table 5}

Comparing both groups in our study regarding their follow-up echo at 1 week and 3 months postoperatively, we detected a statistically significant difference regarding LVEDD, LVESD, pulmonary artery systolic pressure, and pressure across the valve between both groups ([Table 6] and [Table 7]).{Table 6}{Table 7}

On comparing both groups in our study regarding morbidity, there was no morbidity in group A and a single case of morbidity in group B. There was no mortality in both groups for 3 months postoperatively.

 Discussion



PH increases the risk of complications in patients undergoing mitral valve surgery perioperatively; many surgeons refuse to operate on such high-risk patients. With the enhancement in medical technology and the development of pharmacological treatment, the operative risk in these patients should be decreased [8] .

We designed our study to evaluate and compare the early hemodynamic results and echocardiographic data after MVR in patients with mild and severe PH. We grouped our patients according to the preoperative mPAP into group A (mild group), which included 20 patients with mPAP less than 40 mmHg, and group B (severe group), which included 20 patients with mPAP more than 55 mmHg.

The mean age of patients in group A (mild group) (mean ± SD) was 32.50 ± 7.50 years and in group B (severe group) 32.30 ± 6.35 years, with no statistically significant difference between both groups. These results were similar to those of Tempe et al [7]. in their study on 60 patients divided  into severe PH group (30 patients) with PAP greater than 50 mmHg and mild PH group (30 patients) with PAP less than 50 mmHg, the mean age of the mild group was 30.8 ± 11.2 years and that of the severe group was 27.9 ± 10.9 years.

This young age group in the studies can be explained by the fact that in developing countries, a significant number of people do not receive adequate nutrition, sanitation, and medical care. Consequently, they may suffer from recurrent attacks of rheumatic fever, and severe valvular disease develops within a few years of the initial episode.

Women were predominant in our total study group as 23 (57.5%) patients were female. This was similar to the results of Lafηύ et al . [9] , who reported that that in their study group of 50 patients who underwent MVR, 33 (66%) were female; their patients were divided into two groups according to mPAP (<50 mmHg as group A and >50 mmHg as group B).

The higher incidence in women raises the suspicion of hormonal influences in the pathogenesis of PH; another possible explanation is sex difference in health-seeking behavior for reporting health problems and seeking treatment.

Preoperatively, all patients were complaining of dyspnea; when they were classified according to the NYHA classification, we detected a statistically significant difference between both groups (P = 0.012). In group A, four (20%) patients were NYHA I, 14 (70%) patients were NYHA II, and only two (10%) patients were NYHA III. However, in group B, 11 (55%) patients were NYHA II, and nine (45%) were NYHA III. The statistically significant difference between both groups indicates the effect of increased pulmonary pressure on patients' symptoms.

Our results were similar to those reported by Dokhan et al. [10] as 35 (70%) patients were NYHA II, whereas 15 (30%) patients were NYHA III, with no patients in class NYHA I or NYHA IV in their study on 50 patients undergoing elective MVR.

Our results differ from those reported by Mubeen et al. [11] on comparing our severe PH group with that of their study on 43 patients who underwent MVR for rheumatic mitral valves disease with severe PH (mPAP <50 mmHg) as they reported 26 (60%) patients with NYHA III and 17 (40%) with NYHA IV.

On comparing operative data, there was no statistically significant difference between both groups regarding the bypass time, the aortic cross-clamp time, and the total operative duration. Our results coincide with those of Bayat et al. [12] ; in their study of 45 patients who underwent elective MVR, 25 patients had severe PH (mPAP <50 mmHg) and 20 had mild PH (mPAP >50 mmHg), and they reported no significant difference between both groups regarding operative data.

The mPAP in group A patients after induction was 28.75 ± 3.41 mmHg, which decreased to normal values (21.75 ± 2.14 mmHg) immediately after bypass, and then decreased gradually till it reached 16.70 ± 2.83 mmHg at 24 h postoperatively.

Our results coincide with those obtained by Tempe et al. [7] in the mild PH group of their study as the mPAP decreased from 29 ± 10 mmHg after induction to normal values (15 ± 5 mmHg) immediately after bypass, with a gradual decrease till it reached 17 ± 6 mmHg at 24 h postoperatively. However, our results differ from those obtained by Bayat et al. [12] in the mild PH group of their study, as the mPAP increased from 40.4 ± 7.3 mmHg after induction to 43.10 ± 6.2 mmHg on ICU admission, and did not return to normal values even at 24 h postoperatively (32.5 ± 3.9 mmHg).

The decrease in mPAP to normal values after surgery in patients with mild PH can be attributed to the correction of the valvular pathology by the newly implanted prosthetic valve, which relieves the reactive pulmonary vasoconstriction and the passively elevated mPAP.

mPAP in group B patients was 36.85 ± 4.89 mmHg after induction, which decreased gradually to reach normal values after extubation from mechanical ventilation (22.25 ± 5.55 mmHg) and at 24 h postoperatively (20.15 ± 5.65 mmHg).

Our results coincide with those obtained by Tempe et al. [7] in the severe PH group of their study as they reported a decrease in mPAP from 47 ± 11 mmHg after induction to reach normal values of 22 ± 6 mmHg after bypass, with almost the same values at 24 h postoperatively (23 ± 8 mmHg). However, our results differ from those obtained by Lafηύ et al. [9] in the severe PH group of their study as they reported decreased mPAP from 55.9 ± 8.4 mmHg after induction below the range of severe PH, but without returning to normal values as in our study even at 24 h postoperatively (41.7 ± 1.10 mmHg).

On comparing both groups regarding their mPAP at various stages of our study, we detected a highly statistically significant difference between both groups in all stages of our study. These results coincide with those of Tempe et al. [7] as they detected a highly statistically significant difference between both groups regarding mPAP in all stages of their study.

The significant reduction of mPAP detected in all stages of our study could be explained by the vasodilator effect of induction drugs on the vasoactive component of PH followed by relief of the obstructive component by MVR.

On comparing both groups' ABG regarding their pH, PaCO 2 , and HCO 3 values at various stages of our study, we detected a statistically significant difference between both groups after extubation from mechanical ventilation.

Our results differ from those obtained by Bayat et al. [12] as they did not detect significant difference between both groups regarding the pH throughout their study, but they detected a statistically significant difference between both groups regarding PaCO 2 and HCO 3 , but it was after 24 h in the ICU.

A significant difference was detected after extubation from mechanical ventilation with pH more toward acidosis in the severe PH group as PaCO 2 was significantly higher in the severe PH group after extubation, causing a lower pH. PaCO 2 was maintained under  tight control by mechanical ventilation to avoid unwanted effects of hypercarbia on hemodynamics as even mild hypercarbia can significantly increases mPAP.

There was a statistically significant difference between both groups regarding the duration of mechanical ventilation and total hospital stay, although there was no significant difference between both groups regarding the duration of ICU stay.

Our results coincide with those obtained by Tempe et al. [7] as the duration of mechanical ventilation was longer in the severe PH group of their study with a statistically significant difference. Our results differ from those obtained by Bayat et al. [12] as they did not detect a statistically significant difference between both groups.

Patients with mild PH had better baseline oxygenation that could not have improved significantly further. Patients with severe PH had a longer time on mechanical ventilation, reflecting the fact that it took longer for their respiratory status to normalize to meet the weaning and extubation criteria.

On comparing both groups in our study regarding their follow-up echo at 1 week and 3 months postoperatively, we detected a statistically significant difference regarding LVEDD and LVESD. The statistically significant difference detected could be explained by the relieve of high pulmonary pressure in severe PH group post MVR so cardiac dimensions take time to return to normal.

On comparing both groups in our study regarding their follow-up at echo 1 week and 3 months postoperatively, we detected a statistically significant difference regarding pulmonary artery systolic pressure. Our results coincide with those obtained by Lafηύ et al. [9] as they reported a statistically significant difference between both groups on follow-up echo 2 months postoperatively.

On comparing both groups in our study regarding morbidity, there was no morbidity in group A and a single case of morbidity in group B. Our results differ from those obtained by Lafηύ et al. [9] as they reported that morbidity was five (20%) patients in the mild PH group and 13 (53%) in the severe PH group of their study.

There was no mortality in both groups for 3 months postoperatively. Our results coincide with those obtained by Tempte et al. [7], Lafηύ et al. [9] , and Bayat et al. [12] as they reported no early mortality in both groups of their studies.

 Conclusion



MVR is a safe and effective operation even in patients with severe PH. The newer anesthetic agents and techniques, modern cardioplegia, improved mitral valve prostheses, myocardial protection, and postoperative care can be useful in improving the outcome in such patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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