Factors influencing hemolysis in valve prosthesis

A 3D-Printed Externally Adjustable Symmetrically Extensible (EASE) Aortic Annuloplasty Ring for Root Repair and Aortic Valve Regurgitation

PURPOSE

The valve-sparing aortic root replacement (VSARR) procedure was developed to preserve the aortic valve apparatus to replace aneurysmal aortic roots with synthetic grafts and to eliminate associated aortic regurgitation (AR). However, residual post-repair AR is not uncommon and has been found to be associated with recurrent AR and future reoperation.

METHODS

We designed and manufactured a 3D-printed, external adjustable symmetrically extensible (EASE) aortic annuloplasty ring that can symmetrically reduce the aortic annulus diameter via a radial constriction, compliant mechanism. An ex vivo porcine VSARR model with annular dilation and AR was developed (n = 4) and used for hemodynamic, echocardiography, and high-speed videography data collection.

RESULTS

After ring annuloplasty repair using the EASE aortic ring, the regurgitant fraction decreased from 23.6 ± 6.9% from the VSARR model to 7.4 ± 5.6% (p = 0.05), which was similar to that measured from baseline with a regurgitant fraction of 10.2 ± 3.9% (p = 0.34). The leaflet coaptation height after annuloplasty repair also significantly increased from that measured in VSARR model (0.4 ± 0.1 cm) to 0.9 ± 0.1 cm (p = 0.0004), a level similar to that measured in baseline (1.1 ± 0.1 cm, p = 0.28).

CONCLUSION

Using an ex vivo VSARR model, the EASE ring successfully reduced AR by reducing the annular diameter and improving leaflet coaptation. With its broad applicability and ease of use, this device has the potential to have a significant impact on patients suffering worldwide from AR due to root aneurysms.

Frequency and Significance of Intravascular Hemolysis Before and After Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis

Intravascular hemolysis (IVH) has been identified in patients with surgical prosthetic valves, but few have been reported after transcatheter aortic valve implantation (TAVI). We conducted a prospective analysis of 64 TAVI patients. The hemolysis profiles were collected at baseline and 6 months after TAVI. The echocardiography was performed at baseline and 6 months after TAVI. There are 14 patients (21.9%) with IVH before and 24(37.5%) after TAVI. The serum haptoglobin values before and 6 months after TAVI are 126.7 ± 75.1 vs 86.3 ± 57.1 mg/dl (p < 0.001). More ≥moderate paravalvular leakage (PVL) (50% vs 7.5%, p < 0.001), bicuspid aortic valve (BAV) (33.3% vs 5.0%, p = 0.004), use of 23 mm prosthesis (29.2% vs 7.5%, p = 0.03), higher residual valvular pressure gradient (17.9 ± 6.8 mm Hg vs 14.7 ± 5.7 mm Hg, p = 0.05), and lower effective orifice area index (1.05 ± 0.21 vs 1.21 ± 0.29, p = 0.03) were observed in patients with post-TAVI IVH. On multivariate regression analysis, BAV and ≥moderate PVL are independently related to post-TAVI IVH. With log-rank test, 1-year rates of readmission due to cardiovascular cause were significantly higher in patients with post-TAVI IVH (odds ratio 4.5; 95% confidence interval 1.3 to 15.6; p = 0.02), after adjusting age and gender. In conclusion, ≥moderate PVL and BAV are predictors of post-TAVI IVH, which is associated with increased cardiovascular readmission in 1-year follow-up.

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Aortic Stenosis

Chronic intravascular hemolysis has been identified in patients with cardiac valve prostheses, but only a few case reports have evaluated intravascular hemolysis in patients with native valvular heart disease. To detect intravascular hemolysis in patients with aortic stenosis, erythrocyte creatine was evaluated with hemodynamic indices obtained by echocardiography.Erythrocyte creatine, a marker of erythrocyte age, was assayed in 30 patients with aortic stenosis and 10 aged matched healthy volunteers. Peak flow velocity of the aortic valve was determined by continuous-wave Doppler echocardiography. Twenty of 30 patients with aortic stenosis had high erythrocyte creatine levels (> 1.8 µmol/g Hb) and erythrocyte creatine was significantly higher as compared with control subjects (1.98 ± 0.49 versus 1.52 ± 0.19 µmol/g Hb, P = 0.007). Peak transvalvular pressure gradient ranged from 46 to 142 mmHg and peak flow velocity ranged from 3.40 to 5.95 m/second. Patients with aortic stenosis had a significantly lower erythrocyte count (387 ± 40 versus 436 ± 42 × 10(4) µL, P = 0.002) and hemoglobin (119 ± 11 versus 135 ± 11 g/L, P < 0.001) as compared with control subjects. Erythrocyte creatine had a fair correlation with peak flow velocity (r = 0.55, P = 0.002).In conclusion, intravascular hemolysis due to destruction of erythrocytes was detected in patients with moderate to severe aortic stenosis and the severity of intravascular hemolysis was related to valvular flow velocity of the aortic valve.

Incidence and risk factors of hemolysis after transcatheter aortic valve implantation with a balloon-expandable valve

There are currently no data evaluating the hematologic and biocompatibility profile of transcatheter aortic valves in vivo. We evaluated the incidence, predictive factors, and clinical consequences associated with hemolysis post-transcatheter aortic valve implantation (TAVI). A total of 122 patients who underwent TAVI with a balloon-expandable valve were included. Baseline blood sampling and echocardiography, followed by early post-TAVI echocardiography and repeat blood sampling, at 6 to 12 months post-TAVI were performed. Hemolysis post-TAVI was defined according to the established criteria. The incidence of hemolysis post-TAVI was 14.8% yet no patient experienced severe hemolytic anemia requiring transfusion. Compared with the nonhemolysis group, those with hemolysis demonstrated significant reductions in hemoglobin (p = 0.012), were more frequently women (67% vs 34%, p = 0.016), and had a higher incidence of post-TAVI severe prosthesis-patient mismatch (PPM) (44% vs 17%, p = 0.026). The rate of mild or more prosthetic valve regurgitation did not significantly differ between those patients with and without hemolysis (56% vs 37%, p = 0.44). Wall shear rate (WSR) and energy loss index (ELI), both indirect measures of shear stress, were higher (p = 0.039) and lower (p = 0.004), respectively, in those patients with hemolysis. Increasing PPM severity was also associated with significant stepwise WSR increments and ELI decrements (p <0.01 for both). In conclusion, subclinical hemolysis occurred in 15% of patients following TAVI. Although prosthetic valve regurgitation had no impact on hemolysis, a novel association between PPM and hemolysis was found, likely driven by higher shear stress as determined by WSR and ELI. These hematologic and biomechanical findings may have long-term clinical implications and could affect future transcatheter aortic valve design.

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Cardiac Valve Prostheses

STUDY OBJECTIVES

To detect intravascular hemolysis in patients with cardiac valve prostheses. Erythrocyte creatine, a marker of erythrocyte age that increases with shortening erythrocyte survival, was evaluated with other hemolytic markers and hemodynamic parameters.

DESIGN

Prospective study.

PATIENTS AND MEASUREMENTS

Erythrocyte creatine was enzymatically assayed in 33 patients with prosthetic valves, including 15 patients with aortic valve replacement, 13 patients with mitral valve replacement, and 5 patients with double-valve (aortic and mitral) replacement, and 33 control subjects. Blood flow velocity and valvular regurgitation were determined by Doppler echocardiography. Other hemolytic markers (lactate dehydrogenase [LDH], reticulocyte count, and haptoglobin) and cardiac muscle markers (myoglobin and myosin light chain 1) were also measured.

RESULTS

Erythrocyte creatine and LDH levels were significantly higher (p < 0.0001) and the haptoglobin level was lower (p < 0.0001) in patients with a prosthetic valve as compared with control subjects. However, there were no significant differences in these markers between those with (n = 17) and without (n = 16) regurgitation. Patients with high erythrocyte creatine levels (> 1.8 micro mol/g hemoglobin) exhibited significantly higher total peak flow velocity (sum of peak flow velocities at mitral and aortic valves) than those with normal erythrocyte creatine levels (p = 0.006). Erythrocyte creatine had a significant correlation with total peak flow velocity (r = 0.64, p < 0.0001), but LDH and haptoglobin had no significant correlation with total peak flow velocity. Patients with high LDH levels (> 460 IU/L) showed significantly higher myoglobin (p = 0.008) and myosin light chain 1 (p = 0.02) than those with normal LDH levels, whereas erythrocyte creatine was not related to cardiac muscle markers.

CONCLUSIONS

Erythrocyte creatine is a quantitative and reliable marker for intravascular hemolysis in patients with prosthetic valves. Mild hemolysis is ascribable to valvular flow velocity rather than regurgitation.

Hemolysis parameters of St. Jude Medical

BACKGROUND

Elevated plasma lactate dehydrogenase (LDH) concentration may reflect hemolysis due to mechanical heart valve dysfunction. Thus, knowledge of LDH levels in patients with properly working prostheses is required. Because hemolysis parameters for the SJM Hemodynamic Plus (HP) and Regent series are currently not available, the purpose of our study was to determine these data.

METHODS

At 12-19 months follow-up after isolated aortic valve replacement with SJM HP(R) or Regent prostheses, we examined 102 patients by transthoracic echocardiography and determined plasma LDH, haptoglobin, bilirubin and hemoglobin.

RESULTS

Five patients with properly working prostheses were excluded because of increased LDH due to non-cardiac reasons. In four patients with paravalvular leakage, LDH was 244, 307, 446 and 628 U/l, respectively. In patients with properly working prostheses, LDH was 287+/-52 (range: 163-374) U/l for HP(R) (n=33) and 274+/-48 (151-386) U/l for Regent valves (n=60, p=0.2). Haptoglobin was <1g/l in all patients; in 91% of HP and 75% of Regent valves, haptoglobin was below detection limit. Bilirubin and hemoglobin as well as red blood cell count (RBC) were normal in all patients except for five patients with renal anemia, two patients with paravalvular leakage and four patients with macrocytosis due to alcohol abuse. There was no correlation between LDH and transvalvular gradient (r=-0.02) or valve size (r=0.25).

CONCLUSIONS

In patients with SJM HP(R) or Regent valves in aortic position, LDH values > 400 U/l indicate valvular dysfunction or leakage if non-cardiac causes for hemolysis are excluded. However, paravalvular leakage can be present without substantially increased LDH. Haptoglobin has no diagnostic value as it is almost always markedly reduced. Hemolysis does not correlate with transvalvular gradient or prosthesis size.

Intravascular hemolysis after mitral and aortic valve replacement with different types of mechanical prostheses

Heart valve replacement with mechanical prosthesis is associated with mild intravascular hemolysis. In this study we evaluated the incidence of hemolysis in patients with different combinations of two mechanical valves. Between 1974 and 1996, 680 patients underwent mitral and aortic valve replacement with mechanical prostheses; we selected 90 patients, divided into six groups according to the prosthetic model (Group A, ball and tilting disc; Group B, ball and bileaflet; Group C, tilting disc and tilting disc; Group D, tilting disc and bileaflet; Group E, bileaflet and tilting disc; Group F, bileaflet and bileaflet; respectively, in mitral and aortic position). Blood tests were performed to check blood hemoglobin, serum lactic dehydrogenase, percent-correlated reticulocyte fraction, serum haptoglobin, and schistocytes. Chi square test was performed for categorical data. ANOVA and Bonferroni tests were performed in order to evaluate significant statistical differences between media and variance of the hematological data. A mild degree of intravascular hemolysis was observed in 30% of patients with double mechanical prostheses. LDH values were above the normal values in all groups, although a significant difference was found only between Group B versus Groups C and D. Reticulocytes and schistocytes and serum haptoglobin values were within the normal range and no differences were found between the groups. Low levels of blood hemoglobin were found in Groups D and F. The difference was statistically significant when compared with Groups A and E. In conclusion, hemolysis is frequent but never severe in patients with mitral and aortic mechanical prostheses. A higher incidence of subclinical hemolysis was found in patients with bileaflet valves regardless of the position of the implant.

Frequency and severity of intravascular hemolysis after left-sided cardiac valve replacement with Medtronic Hall and St. Jude Medical prostheses, and influence of prosthetic type, position, size and number

Intravascular hemolysis occurs often in patients with mechanical heart valve prostheses, but in most cases is of mild degree and subclinical. The severity of hemolysis is reported to be related to the type, position and size of prostheses used, as well as the presence of valve malfunction. Hemolysis was evaluated in 170 patients with St. Jude Medical (SJM) and 80 patients with Medtronic Hall (MH) prostheses, with normal mechanical function. The presence and severity of hemolysis was assessed on the basis of serum lactic dehydrogenase, serum haptoglobin, blood hemoglobin and reticulocyte levels as well as the presence of schistocytes. Overall, patients with SJM prostheses had greater frequency (51.2 vs 18.7%, p < 0.005) and severity (p < 0.005) of hemolysis than patients with MH prostheses, irrespective of position and size. No patient had decompensated anemia. The frequency of hemolysis was similar in both groups with double-valve replacement, whereas severity was greater with SJM than MH prostheses (p < 0.001). The number and position of the prostheses were correlated with severity of hemolysis: Double-valve replacement and mitral position were correlated with greater hemolysis than single-valve replacement (p < 0.01) and aortic position (p < 0.01). Valve size, cardiac rhythm and time from operation did not correlate either with frequency or severity of hemolysis. It is concluded that in normally functioning SJM and MH prostheses: (1) hemolysis is frequent but never severe; (2) SJM demonstrates greater frequency and severity when compared with MH valve; and (3) number, position, but not size, significantly affect the severity of hemolysis.

Propranolol for intractable hemolysis after open heart operation

Postoperative intravascular hemolysis occurring in 2 patients was alleviated by propranolol. One patient underwent mitral valve replacement and had development of intractable hemolysis due to a paravalvular leak. The other patient underwent ventricular septal defect closure and had hemolysis caused by the Dacron patch. Both patients were given oral propranolol, and the degree of hemolysis decreased substantially. Although the exact mechanism of the propranolol effect on mechanical intravascular hemolysis is unclear, propranolol is thought to reduce the shearing stress between erythrocytes and the foreign material by slowing the velocity of the circulation.

Severe haemolytic anaemia after replacement of the mitral valve by a St Jude medical prosthesis

Severe haemolytic anaemia developed in a 33 year old patient after the mitral valve was replaced with a St Jude medical prosthesis. This was the patient's third thoracotomy. She had already had a mitral commissurotomy and a mitral valve bioprosthesis. The patient had an E+ antibody to red blood cells as well as a paraprosthetic leak. The haemolysis became less severe once the population of E+ red cells was completely haemolysed. However, the patient continued to require transfusions to remain out of heart failure. Once the valve was replaced, the haemolysis subsided. Fulminant haemolysis after mitral valve replacement is rare. When it does occur, a paraprosthetic leak should be suspected. Other causes of haemolysis, however, must also be considered and these may contribute to the severity of haemolysis.

Intractable hemolysis caused by perivalvular leakage following mitral valve replacement with St. Jude Medical prosthesis

Nine patients with intractable hemolysis caused by perivalvular leakage following mitral valve replacement with a St. Jude Medical prosthesis are presented. All patients had dark-colored hemoglobinuria, which appeared from 1 day to 44 days after the operation, with moderate or severe hepatorenal insufficiency. One patient died of multiorgan failure. The other 8 patients underwent reoperation, and all survived. Reoperation revealed that all leakages were tiny and had no adverse effect on hemodynamics. In all the patients having reoperation, hemoglobinuria disappeared immediately after the procedure. Surface-scanning electron microscopy of the sewing cuff of the St. Jude Medical prosthesis revealed the rough surface structure of the sewing ring. Because of this irregular, shaggy surface structure, greater shearing forces against erythrocytes can be generated when there is perivalvular leakage.

Fatal hemolysis due to unidentified causes following mitral valve replacement with bileaflet tilting disc valve prosthesis

Fatal hemolysis after mitral valve replacement with the St. Jude bileaflet tilting prosthesis is reported in two patients. Although one underwent re-replacement of the valve, both died from multiple organ failure and acute renal failure, respectively. Scanning electron microscopy revealed microthrombi adherent to a leaflet in one and irregular leaflet surfaces in the other. Such defects are rare but are possible causes of hemolysis in patients with the St. Jude mitral valve prosthesis.

Anatomic and clinical analysis of 96 Beall prostheses explanted over a 13-year period

Over 13 years, 96 Beall prostheses (80 Teflon, 16 Pyrolite) explanted at surgery were examined for durability, material wear, and clinical symptoms leading to surgical indication for excision were evaluated. The Teflon valves showed progressive disc wear and notching and two cases of disc escape from the cage; the Pyrolite discs were intact in all prostheses. The Dacron-Velour covering common to both types showed dehiscence at the inlet, significantly more severe after the third implant year in the Teflon (p less than 0.005) than in the Pyrolite prostheses. Sixty-nine (85 percent) cases with Teflon valves showed clinical manifestations of congestive heart failure due to prosthetic dysfunction; in 50 there was significant hemolytic anemia. Seven (44 percent) of the 16 Pyrolite disc valves were excised primarily because of dysfunction. The degree of hemolysis with the Pyrolite valves was usually mild. These data clearly suggested the advisability of early excision of the Beall Teflon prostheses in symptomatic patients and a close follow-up in patients with the Pyrolite models.

Bioengineering aspects of heart valve replacement

Biomedical engineering inputs have been important in the design, development and testing of substitute heart valves as well as in the pre- and post-operative management of patients with cardiac valve disease. This paper is a review of heart valve replacement whose goal is the enhancement of future bioengineering contributions. We review the approach to the patient with valvular heart disease, and the sources of early and late postoperative pathology with emphasis on complications of the prostheses used. Major significant problem areas relate to the noninvasive evaluation of cardiovascular function (both before and after surgery), device design, hemodynamics, and the need for thromboresistant and durable materials.

Chronic intravascular hemolysis after aortic valve replacement with Ionescu-Shiley xenograft: comparative study with Bjork-Shiley prosthesis

Twenty patients with a prosthetic valve (Ionescu-Shiley or Bjork-Shiley) in the aortic position were studied for evidence of intravascular hemolysis. Serum lactic dehydrogenase and serum haptoglobin levels were used as the most sensitive indicators of hemolysis. Elevated concentrations of lactic dehydrogenase were found in all 10 patients with an Ionescu-Shiley prosthesis (mean 402 IU/liter) and in 7 of 10 patients with a Bjork-Shiley prosthesis (mean 234 IU/liter). The mean serum haptoglobin was 15 mg/dl (range 10 to 28) in patients with the Ionescu-Shiley valve and 96 mg/dl (15 to 284) for those with the Bjork-Shiley valve. This study indicates the presence of chronic intravascular hemolysis in patients with the Ionescu-Shiley aortic valve. The increase in lactic dehydrogenase was significantly greater in patients with the Ionescu-Shiley prosthesis than in those with the Bjork-Shiley prosthesis, indicating a slightly shorter red cell life span in the former group.

Mechanical haemolytic anaemia after valve repair operations for non-rheumatic mitral regurgitation

Two cases are described in which severe mechanical haemolytic anaemia developed shortly after operation for repair of non-rheumatic mitral regurgitation. One patient had a "floppy" valve and the other cleft mitral leaflets, and both had chordal rupture. In both there was residual regurgitation after repair though in one this was initially only trivial. Clinically manifest haemolysis ceased after replacement of the valve by a frame-mounted xenograft. There are two previously reported cases in which haemolytic anaemia followed an unsuccessful mitral valve repair operation. Subclinical haemolysis or mild haemolytic anaemia may occur with unoperated valve lesions, but hitherto frank haemolytic anaemia has been observed only when turbulent blood flow is associated with the presence of a prosthetic valve or patch of prosthetic fabric. In these four cases, however, polyester or Teflon sutures were the only foreign material, and it is suggested that when these are used for the repair of leaflets, particularly in non-rheumatic mitral valve disease, they may increase the damaging effect of turbulence on circulating red blood cells.

Hemodynamic assessment of the Ionescu-Shiley pericardial xenograft in the mitral position

While the very low thrombogenicity without anticoagulant therapy and generally good durability of the lonescu-Shiley bioprosthesis has been demonstrated, further hemodynamic assessment is necessary. The present study assessed cardiac function and heterograft performance during right and left heart catheterization at rest and exercise (three to six months postoperation) of eight patients with severe mitral stenosis and/or regurgitation prior to surgery. We found, comparing pre- and postoperative resting values, that mean pulmonary artery pressure decreased (32 +/- 2.7 to 22 +/- 3.5 mm Hg; P < 0.02), cardiac index increased (2.1 +/- 0.09 to 2.5 +/- 0.13 liters/min/m2; P < 0.01), pulmonary wedge pressure decreased (21 +/- 2.3 to 13 +/- 1.8 mm Hg; P < 0.01), and the clinical status (NYHA) improved markedly. Mean diastolic gradient across the pericardial xenograft was 6.1 +/- 1.1 mm Hg at rest and 14.6 +/- 2.3 mm Hg on exercise. The calculated xenograft surface area was 1.7 cm2 at rest and 2.0 cm2 during exercise. No regurgitation was detected in seven of eight patients. Thus, mitral lonescu-Shiley bioprosthesis provide excellent heterograft function.

Intravascular haemolysis after valve replacement: comparative study between Starr-Edwards (ball valve) and Björk-Shiley (disc valve) prosthesis

Seventy-four patients with single prosthetic valves (Björk-Shiley or Starr-Edwards) in the mitral or aortic position and 18 controls with rheumatic valvar heart disease were investigated for evidence of intravascular haemolysis. Serum lactate dehydrogenase (LDH) was used as the most sensitive indicator of haemolysis. Raised concentrations were found in a third of 39 patients with Björk-Shiley prostheses (mean 281 IU/l) and in all 35 patients with Starr-Edwards prostheses (mean 859 IU/l. Values were considerably higher in patients with Starr-Edwards prostheses and particularly in those with aortic prostheses (mean 927 IU/l). Eight out of 12 patients with haemosiderinuria had Starr-Edwards valves. Intravascular haemolysis was of little clinical significance in patients with Björk-Shiley prostheses, but some patients with Starr-Edwards prostheses became iron deficient as a result.

Red cell survival after aortic valve replacement with Björk-Shiley prosthesis in presence of sickle-cell trait

A case of aortic valve replacement with a Björk-Shiley disc prosthesis in a patient with sickle-cell trait is presented. Six months after operation red cell survival was not significantly reduced. On theoretical and clinical grounds it is concluded that the presence of sickle-cell trait does not contribute to late postoperative haemolysis after heart valve replacement.

Cholelithiasis: a frequent complication of artificial heart valve replacement

The results of this investigation reveal that 39 per cent of patients in a study group of 46 patients with heart valve prostheses had gallstones if they survived 18 months or longer following valve replacement. In contrast, the prevalence of gallstones in a general population of autopsied rheumatic heart disease patients, including those who had been operated for severe valvular heart disease and had not survived for more than one month, was only 12 per cent. These findings suggest that gallstones are a frequent late complication of heart valve replacement.

An unusual lethal complication associated with Starr-Edwards prosthetic aortic valve holder

This is the first report of an unusual fatal complication associated with the Starr-Edwards prosthetic aortic valve holder. The patient died 51 days after replacement of his aortic valve with a Starr-Edwards prosthetic aortic valve. The cause of death was coronary arterial embolus caused by a fragment broken off of the prosthetic aortic valve holder.

Haemolysis after mitral valve replacement with the Björk-Shiley and the Lillehei-Kaster disc valve prosthesis

The present study reports on the incidence and degree of intravascular haemolysis in 33 patients with Björk-Shiley tilting disc prosthesis and in 34 patients with Lillehei-Kaster pivoting disc valve prosthesis in the mitral position examined 12 to 24 months after the operation. Serum haptoglobin, serum lactate dehydrogenase, serum bilirubin, and haemoglobin estimations were performed. Significant haemolysis was detected in 85 per cent of the patients. Haptoglobin was absent or reduced in 72 per cent, while raised values for serum lactate dehydrogenase were found in 43 per cent. The increase in lactate dehydrogenase was moderate and showed no correlation with blood flow through the prosthesis or with the gradient across the prosthesis. Most patients had normal haemoglobin and normal serum bilirubin values. Although intravascular haemolysis was of little clinical significance, the increase in lactate dehyrdrogenase was significantly higher in patients with the Lillehei-Kaster prosthesis than in patients with the Björk Shiley prosthesis, indicating a slightly shorter red cell lifespan in the former group. The possible reasons for the difference between the two groups are discussed.

Experimental evaluation of mechanical haemolysis with Starr-Edwards, Kay-Shiley and Björk-Shiley valves

Mechanical cell damage was studied in vitro with three types of prostheses: Starr-Edwards, Kay-Shiley and Björk-Shiley valves. Mechanical cell damage was found to be closely related to the flow characteristics in the prosthesis. Considering valves of similar orifice diameter, Björk-Shiley valves produced the lowest rate of haemolysis. This is due to the improved haemodynamic characteristics of the valve which resulted from the laminar type of flow. With Starr-Edwards valves, smaller sizes produced unacceptably high rates of haemolysis. Increasing the mean forward flow across the valve resulted in a disproportionate rise in the energy loss and the rate of haemolysis when compared with Björk-Shiley valves of similar annulus diameters.

Hemolysis in the aortic prosthetic valve

A review of the incidence and severity of hemolysis in the aortic prosthesis is presented. The noncloth-covered Starr-Edwards prosthetic series 1000, 1200, and 1260 had a 2 percent (1/54) incidence of anemia. The cloth-covered Starr-Edwards aortic prosthetic series 2300 was associated with anemia in 61 percent (28/46) of patients. The modified aortic prosthetic series 2310 and 2320 had a 34 percent (19/56) incidence. Mean lactic dehydrogenase levels for the series 1000, 1200 and 1260 were 184 units; 2300 series, 574 units; 2310 and 2320 series, 334 units; and the Bjork-Shiley aortic prosthesis, 166 units. Nine patients underwent repeat surgery because of refractory anemia in the 2300 series, and one did so in the 2310 series. Four of the patients with repeat surgery had significant cloth wearing of the valve. A transvalvular gradient in excess of 30 mm Hg was present in seven of ten anemic patients studied who had the series-2300 valve. The cloth-covered Starr-Edwards aortic prosthesis carries a significant risk of anemia. At the present time the 2310 and 2320 series cause less hemolysis and a lower incidence of anemia than the original 2300 series but in excess of the noncloth-covered Starr-Edwards prosthesis.

Haemolysis with Björk-Shiley and Starr-Edwards prosthetic heart valves: a comparative study

Slater, S. D., Sallam, I. A., Bain, W. H., Turner, M. A., and Lawrie, T. D. V. (1974).Thorax, 29, 624-632. Haemolysis with Björk-Shiley and Starr-Edwards prosthetic heart valves: a comparative study. A comparison was made of the haemolytic complications in 85 patients with two different types of Starr-Edwards cloth-covered ball and cage prosthesis with those in 44 patients with the Björk-Shiley tilting disc valve. Intravascular haemolysis, as detected by the presence of haemosiderinuria, occurred significantly less often with the Björk-Shiley than with the Starr-Edwards valve, the overall incidence with aortic, mitral or multiple replacements being 31%, 15%, and 20% for Björk-Shiley and 94%, 92%, and 88% for Starr-Edwards valves respectively. There was no significant difference in the frequency of haemolysis between each of the two types of Starr-Edwards prosthesis studied at either the aortic (2300 versus 2310 model) or mitral (6300 versus 6310) site.

Haemolytic anaemia developed in only one patient with a Björk-Shiley valve but was common though usually mild with Starr-Edwards prostheses, particularly aortic valve replacements with the 2300 model and in aortic plus mitral (± tricuspid) replacements. The greater severity of haemolysis produced by Starr-Edwards valves, again especially of the latter types, was further demonstrated by higher serum lactate dehydrogenase and 24-hour urinary iron levels.

It is concluded that the Björk-Shiley tilting disc valve represents a significant advance in the amelioration of the haemolytic complications of prosthetic valves.

Chronic hemolysis following mitral valve replacement. A comparison of the frame-mounted aortic homograft and the composite seat Starr-Edwards prosthesis

The incidence and severity of chronic intravascular hemolysis was evaluated in a total of 41 patients following mitral valve replacement. Valve replacement was with a gamma-radiated frame-mounted aortic homograft in 21 patients and with a composite seat Starr-Edwards prosthesis, model 6310 or 6320, in 20 patients. The parameters used to assess hemolysis were hemoglobin, hematocrit, reticulocyte count, red cell fragment count, serum haptoglobin, LDH and HBD, hemosiderin in the urine and red cell survival. The degree of hemolysis was classified as mild, moderate or severe. In the prosthetic valve group 85% showed evidence of chronic intravascular hemolysis, of which a third were mild and the rest moderate. The homograft patients did not show any comparable evidence of hemolysis. Statistical analysis of the comparative figures of the parameters used to assess hemolysis in the two groups of patients revealed a significant difference ( P < 0.01) in hemoglobin and hematocrit and a highly significant difference ( P < .001) in serum haptoglobins, hemosiderin in the urine, LDH, reticulocyte count, red cell fragment count and red cell survivals.

Haemolysis related to mitral valve replacement with the Beall valve prosthesis

Henderson, B. J., Mitha, A. S., le Roux, B. T., and Gotsman, M. S. (1973).Thorax, 28, 488-491. Haemolysis related to mitral valve replacement with the Beall valve prothesis. Experience of valve replacement with the Beall compressed Teflon disc valve in 59 patients confirms that the incidence of clinically significant late red cell destruction is high. An apparently previously unrecorded high incidence of early haemolysis, so severe in one patient as to be directly the cause of death, is reported. In 29 patients there was massive haemolysis in early convalescence, not recognized in urine from some hours after the end of bypass and never encountered with other designs of prosthetic valve or homograft valve.