Usefulness of a multidetector-row computed tomography scanner for detecting pannus formation

BACKGROUND: Prosthetic valve dysfunction (PVD) as a result of pannus or thrombus formation is an infrequent but serious complication. Currently available diagnostic tools, however, are insufficient to detect a minute pannus and thrombi. The use of a more advanced diagnostic image, multidetector-row computed tomography scanner, may enable us to determine the anatomic and functional causes of PVD. METHODS: Patients who underwent aortic valve replacement with a St. Jude Medical valve were examined by transthoracic echocardiography and cineradiography to diagnose PVD. Sixteen patients with PVD (PVD group) and 12 patients with normal prosthetic valve function (control group) were studied using the multidetector-row computed tomography scanner. The multidetector-row computed tomography findings in 2 patients with PVD were validated by the observations during reoperation. RESULTS: In 13 of 16 patients (81%) in the PVD group and 3 of 12 patients (25%) in the control group, multidetector-row computed tomography demonstrated that an abnormal small tissue, regarded as pannus, was found to extend from the left ventricular septum into the pivot guard. These findings were confirmed by the observations during reoperation in 2 patients in the PVD group. CONCLUSIONS: Multidetector-row computed tomography can be a useful diagnostic technique for anatomic and functional evaluation of PVD as a result of pannus formation.     

Obstruction of the left ventricular outflow tract due to pannus formation after the implantation of a carbomedics aortic valve

Excessive pannus formation after implantation of a prosthetic valve is an infrequent but serious complication. A 69-year-old woman who had received a 19-mm CarboMedics aortic valve 11 years ago was readmitted to our hospital with dyspnea and chest oppression. Cineradiography did not show the restriction of valve movement. The aortic peak pressure gradient was calculated by Doppler echocardiography to be 104 mmHg. Based on the diagnosis of stenosis of the left ventricular outflow tract, the patient underwent reoperation. At reoperation, the pannus had formed circumferentially without disturbing the movement of the leaflet. A 19-mm St. Jude Medical Regent valve was implanted after enlargement of the aortic annulus. The patient’s postoperative course was uneventful. We report this characteristic finding of pannus formation after the implantation of a CarboMedics valve in the aortic position.     

Obstruction of the left ventricular outflow tract due to pannus formation after the implantation of a carbomedics aortic valve

Excessive pannus formation after implantation of a prosthetic valve is an infrequent but serious complication. A 69-year-old woman who had received a 19-mm CarboMedics aortic valve 11 years ago was readmitted to our hospital with dyspnea and chest oppression. Cineradiography did not show the restriction of valve movement. The aortic peak pressure gradient was calculated by Doppler echocardiography to be 104 mmHg. Based on the diagnosis of stenosis of the left ventricular outflow tract, the patient underwent reoperation. At reoperation, the pannus had formed circumferentially without disturbing the movement of the leaflet. A 19-mm St. Jude Medical Regent valve was implanted after enlargement of the aortic annulus. The patient’s postoperative course was uneventful. We report this characteristic finding of pannus formation after the implantation of a CarboMedics valve in the aortic position.     

Obstruction of St. Jude Medical Valves in the Aortic Position: Plasma Transforming Growth Factor Type Beta 1 in Patients With Pannus Overgrowth

The study investigated the hypothesis that plasma transforming growth factor type beta 1 (TGF‐β1) initiated pannus overgrowth in cases with aortic prosthetic valve dysfunction (PVD). Patients with obstruction of an aortic St. Jude Medical valve in 26 cases (PVD group) and without obstruction in 48 cases (control group) were studied. Plasma TGF‐β1, the intensity of the prothrombin time–international normalized ratio (PT‐INR), and the interruption of an oral anticoagulant medicine were conducted. Plasma TGF‐β1 levels in the PVD group (87.7 ± 29.2 ng/mL) were significantly higher (P < 0.05) than in the control group (73.7 ± 25.2 ng/mL). The interruption of an oral anticoagulant medicine in 54% of the PVD group versus 12% of the control group was identified (P < 0.001). The mean value of the PT‐INR in the PVD group (1.75 ± 0.30) and control group (1.75 ± 0.30) was not significantly different (P = 0.82). In conclusion, elevated levels of plasma TGF‐β1 may play a role in pannus overgrowth.     

Tricuspid valve replacement with bioprostheses: long-term results and causes of valve dysfunction

BACKGROUND: Although the clinical performance of bioprostheses after valve replacement in the aortic and mitral position has been reported, little is known of the performance of tricuspid bioprostheses. The mechanism of bioprosthetic valve dysfunction after tricuspid valve replacement (TVR) is not clear. METHODS: We reviewed 98 cases of TVR with bioprostheses. To clarify the causes of valve dysfunction, pathologic examination of the explanted valve at the reoperation was performed. RESULTS: Actuarial survival at 18 years was 68.7% +/- 5.8%. There were 12 redo TVRs. In six of the 12 cases, isolated redo TVR was performed. In the other cases, concomitant cardiac procedures were performed. The causes of prosthetic valve dysfunction were pannus formation on the cusps of the right ventricle side (four cases), native valve attachment (two cases), pannus formation + native valve attachment (two cases), sclerotic change (one case), pannus formation + sclerotic change (one case), and native valve attachment + valve infection (one case). Freedom from reoperation, structural valve deterioration, and nonstructural dysfunction at 18 years was 62.7% +/- 10.7%, 96.0% +/- 2.9%, and 76.7% +/- 8.3%, respectively. CONCLUSIONS: In our 18 years of experience, although the survival after TVR with bioprostheses is acceptable, the reoperation free rate is not satisfactory. Pannus formation on the cusps of the ventricular side seems to be a serious problem that causes bioprosthetic dysfunction in the tricuspid position.     

Rare early prosthesis obstruction after mitral valve replacement: a case report and literature review

ABSTRACT: As a dreadful complication after the mechanical heart valve replacement, prosthetic valve obstruction caused by pannus formation occurs increasingly with time. The authors here present a case of 42-year-old woman who was urgently admitted to hospital with acute heart failure symptoms due to the mechanical mitral valve failure only 3 months after surgery. Transthoracic and transesophageal echocardiography demonstrated that the bileaflet of the mitral prosthesis were completely immobilized with only a small transvalvular jet remained. During the reoperation, the reason of the prosthetic valve obstruction was attributed to the noncircular pannus ingrowth extending from the atrioventricular side. For a better understanding of the prosthetic valve dysfunction caused by pannus formation, the authors then compile a literature review to briefly discuss the status quo of the clinical characteristics of this uncommon complication.     

Pannus Resection Through the Tilting Disc Prosthesis: Successful Treatment Preserving the Prosthesis

Abstract: A 59-year-old woman was admitted to our hospital because of heart failure. In 1988, she underwent aortic valve replacement with an Omnicarbon valve and mitral valve replacement with a bioprosthetic valve. She was doing well until July in 1996 when she developed heart failure. Echocardiography revealed massive mitral valve regurgitation, and cinefluoroscopy showed implanted Omnicarbon valve dysfunction with a leaflet opening angle of 35 degrees. At reoperation, it was revealed that pannus formation prevented the valve from functioning well. The pannus was resected through the major orifice, and the leaflet was rotated toward the right anterolateral orientation. The worn bioprosthetic valve was replaced with a mechanical one. Postoperative cinefluoroscopy of the rotated Ominicarbon valve showed the opening angle to be 61 degrees.     

Reoperation on a Starr–Edwards ball valve without structural deterioration

Accurate measurement of pressure gradients on echocardiography across a Starr?CEdwards (SE) ball valve is difficult due to its unique flow pattern. The decision of indication for reoperation on the valve requires multifactorical evaluation. We report a surgical case with an aortic SE ball valve 43?years after implantation. There was no apparent structural deterioration on the ball per se, yet, remarkable pannus formation was noted beneath the sewing cuff in the left ventricular outflow tract.     

Intermittent opening of a mechanical mitral valve prosthesis due to pannus formation; report of a case

A 76-year-old woman with a history of severe mitral valve stenosis had undergone mitral valve replacement with a 27 mm St. Jude Medical (SJM) valve in 1991. Follow-up transthoracic echocardiography revealed an increase in the pressure gradient across the mitral prosthesis 16 years after the surgery. Prosthetic valve dysfunction was suspected, but transesophageal echocardiography and cineradiography failed to show mechanical valve dysfunction. Two years later, she presented with dyspnea on exertion and leg edema. Cineradiography revealed intermittent restriction of the opening of the mechanical valve leaflet approximately every 10 beats. Thus, we diagnosed intermittent prosthetic valve dysfunction and performed a reoperation. On inspection of the prosthesis, we observed semicircular pannus formation around the posterior leaflet in the ventricular side. It was considered that the pannus tissue had interfered with 1 leaflet opening of the mitral valve prosthesis, resulting in intermittent valve dysfunction. We replaced the prosthesis with a new 25 mm SJM valve. The patient was discharged after confirmation of normal prosthetic function.     

Torn Cusp in a Freestyle Stentless Bioprosthesis 5 Years After Implantation: Report of a Case

The Freestyle stentless bioprosthesis (Freestyle valve) is widely used throughout the world because of its durability and benefits for hemodynamic function. However, we encountered a patient who required reoperation for a cuspal tear 5 years after the implantation of a Freestyle valve. The histological findings suggested that tissue degeneration with pannus formation might play a critical role in cuspal tears.     

Obstruction of St Jude Medical valves in the aortic position: histology and immunohistochemistry of pannus

OBJECTIVE: This study aims to reveal the morphological, histological, and immunohistochemical mechanism of pannus formation using resected pannus tissue from patients with prosthetic valve dysfunction. METHOD: Eleven patients with prosthetic valve (St Jude Medical valve) dysfunction in the aortic position who underwent reoperation were studied. We used specimens of resected pannus for histological staining (hematoxylin and eosin, Grocott's, azan, elastica van Gieson) and immunohistochemical staining (transforming growth factor-beta, transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, epithelial membrane antigen, CD34, factor VIII, CD68KP1, matrix metalloproteinase-1, matrix metalloproteinase-3, and matrix metalloproteinase-9). RESULTS: Pannus without thrombus was observed at the periannulus of the left ventricular septal side; it extended into the pivot guard, interfering with the movement of the straight edge of the leaflet. The histological staining demonstrated that the specimens were mainly constituted with collagen and elastic fibrous tissue accompanied by endothelial cells, chronic inflammatory cells infiltration, and myofibroblasts. The immunohistochemical findings showed significant expression of transforming growth factor-beta, transforming growth factor-beta receptor 1, CD34, and factor VIII in the endothelial cells of the lumen layer; strong transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, and epithelial membrane antigen in the myofibroblasts of the media layer; and transforming growth factor-beta, transforming growth factor-beta receptor 1, and CD68KP1 in macrophages of the stump lesion. CONCLUSIONS: Pannus appeared to originate in the neointima in the periannulus of the left ventricular septum. The structure of the pannus consisted of myofibroblasts and an extracellular matrix such as collagen fiber. The pannus formation after prosthetic valve replacement may be associated with a process of periannular tissue healing via the expression of transforming growth factor-beta.     

Long-term survival after triple-valve replacement

A 29-year-old man with rheumatic stenosis and insufficiency of the aortic, mitral, and tricuspid valves underwent urgent triple-valve replacement on January 12, 1966, because of uncontrollable congestive heart failure. Twenty-two years and 8 months later (September 13, 1988) reoperation was necessary to replace the Kay-Shiley tricuspid prosthesis because of progressive stenosis of the valve due to pannus formation. The aortic and mitral prostheses continue to function normally. The patient has again returned to full activity.     

Case report of a malfunctioning SJM 19 A aortic valve prosthesis requiring reoperation

The patient was a 56-year-old female diagnosed with poor lung function who had undergone an aortic valve replacement 10 years ago, receiving an SJM 19 A prosthetic valve. She suffered from dyspnea and chest pain with postural change. Her anticoagulation level was maintained therapeutic. A cinefluoroscopy showed that one of the leaflets in the prosthetic valve was not moving. The aortic peak pressure gradient was calculated to be 68 mmHg using Doppler echocardiography. The patient's clinical condition improved after thrombolytic therapy with urokinase, but a complete normalization of her prosthetic discs was not obtained, so the patient was treated surgically. After an aortotomy, a pannus formation covering the entire SJM 19 A valve was observed. The aortic annulus was estimated to be 16 mm in diameter after the excision of the SJM 19 A valve and required before a larger prosthesis could be inserted. A SJM 19 HP valve was then anchored to the enlarged annulus. Her postoperative course was uneventful. We report a case requiring reoperation after a small aortic mechanical valve prosthesis implanted 10 years previously was damaged by thrombosis and pannus. Pannus formation on small aortic prosthesis easily caused hemodynamic obstructions and mechanical failure. Intensive evaluation with Doppler echocardiography and cinefluoroscopy is required for such patients.     

Premeditated reoperation after mitral valve replacement with a Starr-Edwards ball valve for young women who desire to bear a child: Report of two cases

There are many difficulties for young women with a Starr-Edwards ball valve who want to attempt pregnancy. There is no consensus regarding whether they should maintain anticoagulation therapy throughout pregnancy with the risk of a thromboembolism or to undergo a reoperation with bioprosthetic heart valves, followed by a third operation when the valve deteriorates. This report presents two cases of young women who underwent mitral valve replacement (MVR) with Starr-Edwards ball valves (model 6120: 1M) during their childhood. Although they did not have any cardiac symptoms, transthoracic echocardiography and cardiac catheterization data demonstrated that both the patients had asymptomatic mild relative mitral stenosis. They both wished to bear a child. After the patients and their family provided thorough informed consent, redo MVRs were preformed safely with biological prostheses. The presence of significant pannus formation along the strut and sewing ring of the excised valves could also have a positive impact on the decision to undergo reoperation.     

Redo aortic valve replacement with ''porcelain'' aorta in an aortitis patient. A case report

We report a successful reoperation of aortic valve replacement with the severely calcified, 'porcelain' aorta due to Takayasu's disease. The patient was a 46-year-old female diagnosed with aortic prosthetic valve failure. Takayasu's aortitis had been noted at 17 years old and the patient underwent aortic valve replacement for aortic regurgitation at age 32. Chest CT scan revealed severe circumferential calcification of the whole thoracic aorta. Echocardiography revealed 100 mmHg of pressure gradient across the aortic prosthetic valve with pannus formation. Replacement of the aortic prosthetic valve was performed using the selective cerebral perfusion method under deep hypothermia. The postoperative course was uneventful without any neurological disorder. Selective cerebral perfusion was a useful method to avoid cross clamping in severely calcified ascending aortic.     

Reoperations for acute prosthetic thrombosis and pannus: an assessment of rates, relationship and risk.

OBJECTIVE: Mechanical valvular prostheses have the advantage of longevity but carry a risk of thrombosis which is dependant on valve design, materials and host-related interface. While pannus is common to both biologic and mechanical valves, acute prosthetic thrombosis is mostly a complication of mechanical valves; therefore we investigated to find rates and risk of these obstructive complications. METHODS: Between 1/1/70 and 31/12/97, 2680 patients received at least one mechanical prosthesis in the aortic or mitral or tricuspid position and a total of 3014 operations were performed. Follow-up included 18523 years and was 98% complete. Incidence rates, Kaplan-Meier estimates, modeling of the hazard and multivariate analysis in the hazard domain were used in the analysis. RESULTS: Overall survival was 76%, 64%, 51%, 38.5% and 29% at 5, 10, 15, 20 and 25 years, respectively. It was significantly better in aortic than in mitral than in double prosthesis. 290 patients received a single reoperation, 37 a second, six a third and one a fourth reoperation. Two-hundred and fifty-one of these reoperations were exclusively due to malfunction of mechanical prosthesis, nine to malfunction of both mechanic and biologic prostheses. Most frequent reoperative indications was dehiscence (133), pannus (48) and thrombosis (29). The linearized rate of reoperations for pannus was 0.24%/patient per year, for valvular thrombosis 0.15%/patient per year. The shape of the thrombotic hazard was constant (at random) and the relative risk 12 times higher for tricuspid prosthesis, seven times higher for mitral prosthesis. Multivariate analysis controlling for prosthetic position, age, sex and prosthetic size, showed a 67% risk reduction with larger prosthesis (>27 mm), a 69% risk reduction with the Sorin tilting disk prosthesis and an 83% risk reduction with the bileaflet prosthesis. Pannus hazard shows a delayed exponential rise and was two times higher in tricuspid and three times higher in mitral position. Multivariate analysis showed a 50% risk reduction with larger prosthesis, an 11 times higher hazard of old (caged-disk, caged ball) prosthesis and a three times higher hazard of Lillehei-Kaster prosthesis. Reoperation for thrombosis has a 62% perioperative (30 days) survival compared to 92% survival of pannus reoperation. CONCLUSIONS: Mechanical valves have a low incidence of reoperation, mostly for prosthetic dehiscence. Pannus development is the next frequent complication increasing with time since implant, therefore in this series it was related to old valvular models and tilting disk prosthesis, with longer follow-up. Acute thrombosis occurs significantly earlier than pannus formation. Despite shorter follow-up we are therefore confident that bileaflet prostheses are less prone to this complication and pannus is a rare early etiologic factor. Thrombosis has very high operative risk as compared to pannus, justifying the present trend to thrombolysate selected cases.     

Prophylactic reoperation after mitral valve replacement with the Starr-Edwards ball valve: a report of four cases.

PURPOSE: The Starr-Edwards ball valve was first applied clinically in 1960. In our hospital, this valve has been used since 1963, and some patients have been followed up for 30 years or more. Based on our experience, therapeutic strategies included revalve replacement as a preventive procedure in the absence of valve-related complications. In this study, we investigated whether prophylactic reoperation after valve replacement with the Starr-Edwards ball valve is appropriate. PATIENTS AND METHODS: Of 58 patients in our institute who underwent mitral valve replacement with the Starr-Edwards ball valve, 12 underwent revalve replacement. Of these 12, the subjects of the present study were 4 patients who underwent prophylactic revalve replacement. RESULTS: The mean postoperative follow-up of the 4 patients was 31.0+/-3.7 years. There were no operative deaths or postoperative complications. On examination of the extirpated Starr-Edwards valves, cloth wear was observed in all 4 patients. Although there was no influence on the range of ball motion, they showed the entity of "thrombus/pannus." CONCLUSION: In this study, all of the patients showed cloth wear in the absence of complications. Therefore we consider that prophylactic reoperation after valve replacement with the Starr-Edwards valve should be performed to prevent complications.     

Comparison of noninvasive techniques in evaluation of the Bj?rk-Shiley and the St. Jude Medical valve prostheses in mitral position

Pressure gradients and left ventricular function were assessed by Doppler echocardiography in 50 patients with Bj?rk-Shiley mitral valve and 50 patients with St. Jude Medical valve prosthesis. There was correlation between pressure gradient and valve size, and between effective valve orifice area and valve size for St. Jude Medical valve. These correlations were not found in Bj?rk-Shiley valve. Clinical improvement and cardiac function were quite satisfactory in 20 patients with Bj?rk-Shiley valve and in 32 patients with St. Jude Medical valve whose pressure gradients were less than 10 mmHg. Twenty eight of 50 patients with Bj?rk-Shiley valve and 42 of 50 patients with St. Jude Medical valve showed good response to the exercise test. Eight patients underwent reoperation because of unacceptably high gradient caused by thrombus and pannus formation. The patients who show high pressure gradient across the valve prosthesis should be followed up cautiously.     

Use of the Bentall method for replacement of an aortic Starr-Edwards ball valve prosthesis implanted 32 years previously

We report the case of a 54-year-old woman who, 32 years previously, had undergone replacement of the ascending aorta by the inclusion method with a Starr-Edwards ball valve prosthesis and recently underwent aortic root re-reconstruction by the Bentall method. Routine chest radiography revealed dilatation of the mediastinum, and computed tomography revealed an aneurysm of the ascending aorta. At reoperation, although the cloth covering the cage of the Starr-Edwards ball valve prosthesis appeared worn and some pannus formation was seen, the Starr-Edwards ball valve was functioning normally. The aortic root was replaced with a composite graft that consisted of a 23-mm St. Jude bileaflet prosthesis and a 24-mm Hemashield gold graft. The patient was discharged from the hospital in good condition 25 days after surgery.     

St. Jude Medical prosthetic aortic valve malfunction due to pannus formation.

According to the literature, the incidence of pannus formation with the St. Jude Medical prosthetic aortic valve has been reported at 0.03% and 0.14% (per patient-year), with no case report of St. Jude Medical prosthetic aortic valve malfunction due to pannus formation. Between 1980 and 1999, 1,186 patients underwent aortic valve replacement at our institute. We encountered 2 aortic valve malfunctions due to pannus formation, including the case of a 53-year-old woman who suffered a St. Jude medical aortic valve malfunction 13 years after the initial operation. A second aortic valve replacement was successful and the postoperative course was uneventful. The possibility of pannus formation on St. Jude Medical aortic valves must thus be considered and its mechanism clarified.