|Year : 2017 | Volume
| Issue : 3 | Page : 246-250
Prosthetic valve obstruction: Redo surgery or fibrinolysis?
Avinash Inamdar1, Shweta Pralhad Shende1, Sanjeevini Inamdar2
1 Department of Cardiovascular and Thoracic Surgery, B. J. Medical College, Pune, Maharashtra, India
2 Department of Cardiac Anaesthesia, B. J. Medical College, Pune, Maharashtra, India
|Date of Web Publication||19-May-2017|
Shweta Pralhad Shende
Department of Cardiovascular and Thoracic Surgery, B. J. Medical College, Sassoon General Hospital, Pune - 400 008, Maharashtra
Source of Support: None, Conflict of Interest: None
Objective: The aim of this study was to compare the efficacy and safety of surgery versus fibrinolytic therapy in patients with prosthetic valve obstruction. Materials and Methods: We compared 15 patients of prosthetic valve thrombosis treated by surgical line of management and another 15 patients treated by thrombolysis. All patients were initially assessed by clinical evaluation and diagnosis confirmed by transthoracic and transesophageal two-dimensional echocardiography. Depending on hemodynamic stability, pannus, or thrombus on transesophageal echocardiography, the patients were assigned surgical or medical line of management. Results: Patients mortality rate was 40% in fibrinolytic group and 13.33% in surgical group. Recurrence was 40% in fibrinolytic group while there was no recurrence till date in surgery group. Complications were more in fibrinolytic group as opposed to surgery group patient. Conclusion: From our experience, we conclude that redo surgery is effective and definitive treatment, especially in patients with stable hemodynamic conditions.
Keywords: Pannus, prosthetic valve obstruction, redo surgery, thrombolysis
|How to cite this article:|
Inamdar A, Shende SP, Inamdar S. Prosthetic valve obstruction: Redo surgery or fibrinolysis?. Med J DY Patil Univ 2017;10:246-50
| Introduction|| |
Treatment of advanced rheumatic valvular heart disease is the surgical replacement of the valve. However, there are inherent problems that may arise as a result of the prosthesis. Among the complications of prosthetic valves are biomechanical failure, endocarditis, bleeding complications of anticoagulation, and valve thrombosis or prosthetic valve obstruction. Prosthetic valve thrombosis is defined as any obstruction of a prosthesis by noninfective thrombotic material or valve-related clotting impairing the function of the valve. Prosthetic valve obstruction or stuck prosthesis covers different pathologies such as thrombus, pannus, and vegetation.
Prosthetic heart valve obstruction is a serious complication of mechanical prosthetic valve and its prompt recognition and treatment is important as if undiagnosed it is associated with high mortality rate.
Incidence of prosthetic valve thrombosis depends on valve type, location of valve, and adequacy of anticoagulation. The incidence of the prosthetic valve thrombosis for mitral valve is 5 times and for embolism is 1.5 times higher as compared with that of the aortic valve. Inadequate anticoagulation in patients with mechanical heart valve can result in a significant incidence of thromboembolism and prosthetic heart valve thrombosis which average 0.2% and 1.8%/patient-year, respectively.
Optimal management of these patients with prosthetic valve obstruction is controversial with some advocating fibrinolysis and others surgery.
Against this background, we analyzed the results and follow-up data from a nonrandomized cohort of patients with prosthetic valve obstruction treated with either fibrinolysis or surgery, to evaluate and compare the efficacy and safety of these treatment modalities.
| Materials and Methods|| |
The study sample included 15 symptomatic patients treated with thrombolytic therapy and 15 patients who underwent redo valve replacement surgery for prosthetic heart valve obstruction.
Prosthetic valve obstruction was suspected in all patients who presented with recent change in clinical symptoms, i.e., dyspnea, history of palpitation, or signs systemic embolism. History included severity and duration of symptoms and history of discontinuation of medication.
Patients were examined for peripheral arterial pulse and rhythm. Blood pressure was recorded, and patients were auscultated for change in murmur and click of valve. Crepitations were present in all those who were symptomatic. Electrocardiogram and chest X-ray were done in all patients.
We did baseline, postoperative, and predischarge two-dimensional echocardiography (2D ECHO) of all patients to know the gradient across prosthetic valve and valve area. These Doppler measurements were then reassessed during routine follow-up, initially every month for 6 months and then every 3 months.
Those patients who were mildly symptomatic and in whom we were suspecting valve thrombosis or malfunction were reinvestigated by transesophageal echocardiography (TEE). On TEE, patients were evaluated for the gradient across the prosthetic valve, presence of thrombus or pannus which can be identified from the ultrasound intensity of mass, leaflet mobility of prosthetic valve, size of thrombus and its extension, and presence of the left atrial clot. Once the diagnosis is confirmed by TEE, patients were allocated for fibrinolysis or surgery. Patients, who were hemodynamically unstable, critically ill, or not fit for surgery with no medical contraindication for thrombolysis or with small thrombi, were allocated for fibrinolysis. The hemodynamically stable patient who had pannus formation with large thrombus or mechanical disc problem due to stuck prosthesis was considered for surgery.
For thrombolysis, we gave injection streptokinase 150,000 units intravenous (IV) slowly over 1 h followed by IV heparin 5000 units stat followed by 1000 units/h for 48 h. We monitored activated partial thromboplastin time (aPTT) of these patients at 6 h after starting heparin and then every 8 hourly for 48 h to maintain aPTT between 1.5 and 2 times the normal values.
Simultaneously, we started tablet warfarin 5 mg OD and tab ecosprin 75 mg OD on next day and repeated prothrombin time with international normalized ratio (INR) on the 3rd day to adjust the INR between 2.5 and 3.
Some of these patients with Grade IV dyspnea (by New York Heart Association [NYHA] classification of dyspnea), with thrombus and pannus, were initially treated with thrombolysis, and once patient was hemodynamically stable, redo valve replacement was planned. Those patients who got recurrence after thrombolysis were treated by surgical line of management.
| Results|| |
In the fibrinolytic group, out of 15 patients, 8 (53%) patients were female and 7 (46%) male. The mean duration of patients from operation to prosthetic valve obstruction was 5.8 years. The mean age was 30.9 years (range 20–56 years). There was no specific type of valve prostheses which was involved with prosthetic valve thrombosis. Out of 15 patients, 3 patients had aortic valve prosthesis obstruction (20%). All other patients had mitral valve prosthesis obstruction (80%). All patients in this group were of NYHA Class III and IV. Out of these, five patients (33%) presented with NYHA Class III and rest with NYHA Class IV (67%). Six (40%) patients were critically ill with frank pulmonary edema and hence were intubated. Four patients died; hence mortality rate in the fibrinolytic group was 26%. One patient presented with history of embolic episode to the left lower limb. Out of those 15 patients for thrombolysis, gradient across the valve which was raised initially decreased in all 11 patients, thus these (73%) recovered and got hemodynamic stability temporary, but 6 patients (40%) later on developed recurrent prosthetic valve obstruction with decreased mobility of prosthetic valve leaflet and pannus formation along the edges of prosthetic valve, during follow-up of 6 months duration. Complete cure was obtained in five patients [Figure 1]. Prethrombolytic 2D ECHO finding of these five patients showed acute thrombus, and in follow-up, study showed complete resolution of thrombus. Out of the six recurrences, four were in female who were lost to follow-up, and two patients were operated and are asymptomatic at present.
History of discontinuation of medicine was present in six patients (40%). All were females from remote places, and follow-up was inadequate. All patients (100%) were in atrial fibrillation at time of presentation. INR of all patients except two was in subtherapeutic range.
There was no major complication of thrombolysis in the present study, except for one patient had severe per vaginal bleeding and was transfused with fresh frozen plasma and bleeding was controlled.
In surgery group, there were 15 patients. Out of 15 patients, 8 patients (53%) were male and 7 were female (47%). Mean age of presentation was 36.6 years.
The mean duration from operation to prosthetic valve obstruction was 7.5 years. Mitral valve was most commonly involved. All patients presented in this group were in NYHA functional Class I and II. Seven (47%) patients had NYHA I symptoms, eight (53%) had NYHA II symptoms. Two (13.33%) patients had history of transient ischemic attack. One patient had left side hemiparesis. Thus, three patients (20%) gave history of embolic episode. History of discontinuation of drug was given by two patients (13.33%). 2D ECHO findings showed pannus in 75%, thrombus in 5%, thrombotic material along with pannus in 15%, and limited disc mobility in 5% patients. Only one (6.6%) patient underwent aortic valve redo surgery. The nature of obstruction was assessed at the time of operation. Thrombus was observed and hence thrombectomy was done, but after removal of thrombus, there was mechanical defect with the movement of prosthetic valve and hence valve was replaced.
There were two deaths giving mortality rate of 13.33%. One death was due to right ventricular tear during sternotomy, due to severe adhesion between sternum and heart, and the other patient had Klebsiella pneumoniae infection and died due to adult respiratory distress syndrome. There were no other major complications except for surgical site infection in two patients. All these patients were educated regarding compliance of drug to avoid the complication of rethrombosis of valve. INR of all these patients was maintained in therapeutic range during follow-up. Long-term follow-up showed significant better results in surgical group of patients. Comparison between these two groups is shown in [Table 1] and [Figure 2].
|Table 1: Comparison of fibrinolytic and surgery group along with the outcomes in the two groups|
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|Figure 2: Comparison of outcomes between surgery and fibrinolytic groups|
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| Discussion|| |
Prosthetic valve thrombosis is defined as any thrombus in the absence of infection, attached to or near an operated valve, occluding part of the blood flow, or interfering with valve function. Prosthetic valve obstruction or stuck prosthesis covers different pathologies such as thrombus, pannus, and vegetation.
Any patient after mechanical heart valve replacement surgery if presents with any new onset of symptoms should be evaluated thoroughly clinically as well as by 2D ECHO and fluoroscopy. On auscultation in patients with prostheses valve obstruction, the prosthetic clicks are muffled, or absent with murmur of obstruction may be heard. TEE is more sensitive and specific and is the investigation of choice.
This rare but life-threatening complication of prosthetic valve replacement is dependent on valve design, where tilting disc and ball and cage type of mechanical valve are often implicated. Structure (mechanical valve), location (mitral position), and patient compliance with oral anticoagulation are other factors contributing to prosthetic valve obstruction. Inadequate anticoagulation therapy is an important factor in the pathogenesis of thrombosis. This phenomenon may be acute, leading to a fresh thrombus or chronic associated with an organized thrombus.
In Indian setup where majority of patients with valve replacement belongs to poor socioeconomic status and females are often neglected, they are liable to be lost to follow-up after replacement which leads to subtherapeutic anticoagulation and predisposes patients to prosthetic valve thrombosis. On the other hand, general practitioner may time give certain over the counter drugs without knowing its interaction with warfarin which may cause subtherapeutic anticoagulation.
Pathological studies have underlined that pannus formation plays an important role in mechanism of obstruction. Pannus formation is defined as an excessive wound fibrosis around a prosthetic valve. The presence of pannus is strong indication for prosthetic valve replacement. Prosthetic valve obstruction may present with thrombosis or pannus or thrombosis superimposing on pannus. It is essential to differentiate between the pannus or thrombus preoperatively by TEE to plan management.
According to Renzulli et al., fresh primary thrombosis is usually associated with a recent perturbation of anticoagulation and a recent onset of symptoms of < 15 days which can respond to fibrinolysis. In contrast, pannus presents with progressive deterioration of clinical status, a progressive increase in gradient, and an abnormal hyperechogenic mass attached to prosthesis.
Our results are in agreement with that study reported in literature. Concerning fibrinolysis, Lengyel et al. reported 82% initial success rate and mortality rate of 10%. They concluded that fibrinolysis of the left-sided prosthetic heart valve is acceptable for critically ill patient in Class III and IV in whom surgical intervention carries a high risk or in patients with contraindications to surgery.
Renzulli et al. concluded that surgery was safer than fibrinolysis which is successful only in 53.8% of patients and with embolic complications.
Roudautet al. confirm that prompt surgical treatment is associated with a better early success rate and significant lower incidence of complications than fibrinolysis in prosthetic heart valve obstruction.
Thus, duration of symptoms, anticoagulation status, and qualitative and quantitative ultrasound intensity of mass obstructing a mechanical prosthetic valve can help differentiating pannus formation from thrombus and therefore of value in deciding the selection of patient for thrombolysis therapy of prosthetic valve obstruction.
From our experience of the present study, we conclude that thrombolysis is indicated for those patients with fresh primary thrombosis and who could not tolerate cardiopulmonary bypass due to severe hemodynamic compromise. The most common factors for valve thrombosis are inadequate anticoagulation due to poor patient compliance, and there is a need for both patient and general practitioner education. If patient compliance with long-term medications is an issue, a bioprosthetic valve should be implanted.
Surgery is the mainstay of modality of treatment for hemodynamically stable patient and those showing increasing gradient across valve due to pannus. Unstable patients should undergo thrombolysis, stabilized, and then operated for valve replacement. Thus, thrombolysis acts as a bridging stone or safety pathway in some patients.
| Conclusion|| |
Although the study showed better outcomes in the surgery group, we cannot conclude with conviction from this limited case series which intervention is superior since the two groups were not comparable as the surgery group comprised patients in NYHA I and NYHA II categories while the fibrinolysis group had patients of NYHA III and NYHA IV categories.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]