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R B Hokken

Publications and source records attributed to R B Hokken.

14 recordsLinked to original sources

Dissection in a right sided porcine-valved Dacron conduit.

Seventeen years after corrective surgery for a double outlet right ventricle and pulmonary stenosis, a 30-year-old patient was admitted for reoperation for a critical stenosis of a porcine-valved Dacron conduit between the right ventricle and pulmonary artery. A residual ventricular septal defect was present. Induction of anaesthesia resulted in an inadequate pulmonary flow and uncontrollable ventricular arrhythmias. At autopsy the conduit showed a dissection between the conduit wall and the peel formation, leaving a residual lumen with a diameter of less than a third of the original. Patients with a right sided bioprosthetic valved conduit must be evaluated regularly and operated before the stenosis becomes critical.

Adult↗

A comparison of adult pulmonary autograft diameter measurements with echocardiography and magnetic resonance imaging.

UNLABELLED: In 38 consecutive patients the pulmonary autograft was used in aortic root replacement. Investigations were performed with transthoracic echocardiography, transoesophageal echocardiography and magnetic resonance imaging in 31, 27 and 27 patients respectively. The mean age at operation was 28.7 years (range 19.0-52.0) and the follow-up period was 2.8 years (range 0.8-6.7). The pulmonary autograft diameter was measured at the subannular region (1), at the annulus at the hinge points of the valve leaflets (2), at the sinus (3), at the sino-tubular junction (4) and at the distal part of the autograft (5). With transoesophageal echocardiography the mean systolic measurements at levels 1 to 5 were 32, 31, 42, 35 and 34 mm, respectively. The corresponding diastolic measurements were smaller: 25, 28, 42, 35 and 34 mm respectively. There was no significant difference between transthoracic echocardiography and transoesophageal echocardiography measurements of the proximal autograft (levels 1-3). Diameters obtained with magnetic resonance imaging were 1 to 3 mm larger than those obtained with transthoracic echocardiography and transoesophageal echocardiography (P < 0.05), except the annulus at systole (P > 0.3). CONCLUSIONS: The mean pulmonary autograft diameters measured using transthoracic echocardiography, transoesophageal echocardiography and magnetic resonance imaging were larger than native aortic and pulmonary diameters of a normal population in the same age group. Diameters of the distal 2 levels could not be imaged reliably with transthoracic echocardiography. Magnetic resonance imaging diameter measurements were, in general, larger than with echocardiography.

Adult↗

Clinical outcome and left ventricular function after pulmonary autograft implantation in children.

BACKGROUND: Aortic root replacement with a pulmonary autograft is an alternative treatment for children with aortic valve or root disease, or both. METHODS: Twenty-six patients (18 boys and 8 girls) with a mean age of 10.9 years (range, 0.3 to 16.9 years) underwent this procedures in a 7-year period. The mean follow-up period was 3.2 years (range, 0.2 to 7.5 years). RESULTS: During follow-up 3 patients died and one autograft was replaced with a mechanical valve. The actuarial survival and actuarial event-free survival rates were 87% and 79%, respectively, at both 5 and 7 years. None of the surviving patients had complaints, and all have done well and are living normal lives. Electrocardiographic signs of myocardial ischemia and left ventricular hypertrophy were not present. Echocardiography showed autograft valve regurgitation to be absent or trivial (n = 17) or mild (n = 5). Stenosis was not present. Increasing autograft annulus diameters were noted during follow-up, but this was not related to the severity of autograft regurgitation. Left ventricular dimensions and function were within normal limits later than 1 year after the operation. Only 2 patients had a moderate pulmonary stenosis without right ventricular hypertrophy. CONCLUSIONS: The surgical results, clinical outcome, valve function, and left ventricular function in our patients have been good. This procedure is recommended as a method of aortic valve replacement in children.

Actuarial Analysis↗

Does the pulmonary autograft in the aortic position in adults increase in diameter? An echocardiographic study.

OBJECTIVE: The objective of this study was to discern the fate of the pulmonary autograft diameter over time in adults and its relation to aortic regurgitation in the setting of aortic root replacement. METHODS: From January 1989 to May 1995, 36 consecutive adult patients underwent aortic root replacement with a pulmonary autograft for aortic valve disease. The mean age of 20 male and 16 female patients was 29.1 years (range 19.3 to 52.1 years). The mean follow-up was 2.3 years (range 0.3 to 6.0 years). Two patients died in the hospital. One other patient had a second operation for stenosis at the distal suture line of the allograft in the pulmonary position. Pulmonary autograft anulus and sinus diameters were measured with epicardial echocardiography before (only anulus) and after cardiopulmonary bypass, with transthoracic echocardiography at hospital discharge, and with transesophageal echocardiography during follow-up. RESULTS: The mean autograft anulus diameter did not increase immediately after cardiopulmonary bypass (mean diameter 26.2 mm before and 26.4 mm after cardiopulmonary bypass). The mean autograft sinus diameter after cardiopulmonary bypass was 36.5 mm. The mean autograft anulus diameter increased to 31.5 mm at follow-up, an increase of 5.1 mm (19%). The mean autograft sinus diameter increased to 43.9 mm at follow-up, an increase of 7.4 mm (20%). Fifty-nine percent of the anulus diameter increase and 40% of the sinus diameter increase was already reached at hospital discharge (7 to 10 days after the operation); the other part of the increase occurred during follow-up. Diameter increase was associated with neither the length of follow-up (follow-up less than 1 year compared with a longer follow-up) or severity of aortic regurgitation. CONCLUSION: Pulmonary autograft anulus and sinus diameters increase the first year after aortic root replacement with a pulmonary autograft. This occurs rapidly within 10 days after the operation, with a further increase during follow-up, without causing significant aortic regurgitation at medium-term follow-up.

Adult↗

Morphology of the pulmonary and aortic roots with regard to the pulmonary autograft procedure.

Aortic root replacement with the pulmonary autograft warrants a thorough histologic comparison of the morphologic characteristics of the pulmonary and aortic roots. For this purpose nine normal heart specimens (7 neonatal and 2 adult hearts) were studied. Histologic study confirmed the collagenous anulus in both roots to be a complex circular-shaped structure, intricately interposed between the elastic lamellae of the arterial wall and the ventricular structures of the heart. In this sinus the elastic lamellae of the arterial wall continue along the luminal side with collagen being situated at the outside. At the interleaflet triangle this relation is reversed. Surprisingly, islet of elastic fibers were found in the otherwise completely collagenous interleaflet triangles. The amount of elastic lamella distal to the commissures was in both arteries higher than that in the middle of the sinuses, with a preponderance in the aorta as compared with the pulmonary trunk. The pulmonary root anulus proximally inserts into the relatively thin right ventricular myocardium, whereas the aortic root anulus inserts into the thick left ventricular myocardium and several fibrous structures. The pulmonary root is hardly supported by the right ventricular myocardium, whereas the aortic root is supported by its wedged position between the left and right atrioventricular anuli and the bulging thick left ventricular myocardium. When the pulmonary autograft is used for aortic root replacement it should be inserted as proximally as possible to get the support of the fibrous structures of the left ventricular outflow tract and the surrounding ventricular and atrial myocardium.

Adult↗

Repair of aortic arch interruption by direct anastomosis.

OBJECTIVE: Evaluation of surgical treatment of interrupted aortic arch (IAA) by direct anastomosis. METHODS: A consecutive series of 17 infants with IAA (type A in eight patients, type B in nine) were operated upon. The mean age at arch repair was 1.0 month (range 0.2-7.7), mean weight was 3.7 kg (range 2.2-6.2). All arch repairs were done by direct anastomosis. This included a persistent arterial duct in one and a subclavian turnup in another case. The aortic reconstruction included reimplantation of a lusoric artery in three patients, patch enlargement of the ascending aorta in three and of the complete arch in one patient. The arch repair was done through a lateral thoracotomy in three patients. In 14 patients the aortic repair was part of a single-stage approach through a median sternotomy using cardiopulmonary bypass and circulatory arrest. RESULTS: There was no operative mortality. One patient (single-stage approach) died 2 days after operation due to respiratory problems caused by tracheobronchomalacy. One patient (lateral approach) died suddenly 3 months after aortic repair and banding. Median follow up was 4.8 years (range 0.1-12.9). In five patients restenosis of the aortic arch developed, all within 1.5 years after repair. This was not correlated with the type of interruption, weight at operation, age at operation or the surgical approach. The actuarial freedom from restenosis was 61% at 5 years with a 70% confidence limit (CL70%) of 46-75. All restenoses were balloon dilated, but two needed redo surgery, which was done by the median approach. In three patients discrete subaortic stenosis developed. This was not correlated with the type of interruption, weight at operation, age at operation or the surgical approach. The actuarial freedom from subaortic stenosis was 68% at 5 years (CL70% = 54-83). These stenoses were treated by enucleation, followed in one patient by a pulmonary autograft procedure for recurrent root stenosis after another year. At the end of follow up all patients were thriving well, lacked symptoms, were normotensive and had normal femoral artery pulsations. CONCLUSIONS: IAA can be treated well with primary anastomosis. Possible restenosis of the aortic arch can adequately be treated by percutaneous balloon dilatation or redo surgery if necessary. Arch repair by median single-stage approach has our preference.

Actuarial Analysis↗

25 years of aortic valve replacement using mechanical valves. Risk factors for early and late mortality.

This study describes the changes that have taken place in patient characteristics in 25 years of aortic valve replacement using mechanical valves, and looks for risk factors for early and late mortality. During this period, 1449 mechanical valves were implanted. Overall early mortality (< 30 days) was 5.3% and for aortic valve replacement without concomitant procedures 3.9%. Overall survival rates at 5, 10 and 15 years were 80%, 63% and 49%, respectively. Despite an increased proportion of higher risk patients (older age, more reoperations, more concomitant coronary bypass surgery) survival rates improved throughout the study period. Early mortality was related to an early year of operation, urgency, reoperation and concomitant surgery to the tricuspid valve or ascending aorta. Late mortality was higher for patients of older age, with an early year of operation, male gender, concomitant coronary bypass surgery, mitral valve surgery or replacement of the ascending aorta. Aortic regurgitation did not have a major influence on early nor late mortality. The improvement in early and late mortality in more recent years was largely the result of the introduction of cardioplegia. A changing, non-proportional effect was observed for several risk factors during the follow-up period. This study illustrates the changes and improvements in medical care that have taken place in patients requiring aortic valve replacement.

Aortic Valve↗

Allograft reconstruction of the right ventricular outflow tract.

OBJECTIVE: Evaluation of allograft reconstruction of the right ventricular outflow tract (RVOT). METHODS: From 1986 to April 1995, 201 allografts (146 pulmonary, 55 aortic) were implanted in 189 patients for conduit reconstruction of the RVOT in congenital heart disease or in the pulmonary autograft procedure. The mean age at allograft implantation was 16 years (range 2 weeks - 54 years). The primary diagnoses of these patients were truncus arterious (n = 19, 10%), transposition of the great arteries (TGA) with ventricular septal defect (VSD) and pulmonary atresia (PA) or stenosis (PS) (n = 14, 7%), PA with VSD (n = 26, 14%), PA or PS with intact septum (n = 7, 4%), tetralogy of Fallot (n = 44, 23%), corrected TGA with PA or PS (n = 11, 6%), tricuspid atresia (n = 9, 5%), aortic valve pathology for pulmonary autograft procedure (n = 55, 29%), and miscellaneous (n = 4, 2%). The allograft implantation was a reoperation in 54 patients (29%). RESULTS: The mean follow-up was 2.5 years (range 4 weeks-9 years). Six patients died in hospital (3.2%). Patient survival at 5 years was 91% (95% CL 86-95%). Freedom from all valve-related events (2 deaths, 17 reoperations, one endocarditis), as determined during reoperation or autopsy at 5 years was 78% (95% CL 65-86%). Freedom from structural allograft failure was 83% (2 deaths, 12 reoperations, 95% CL 70-90%). Allografts implanted for congenital right heart defects failed earlier than allografts used for pulmonary autograft procedures (P = 0.05). Aortic allografts showed structural failure more often than pulmonary allografts (P = 0.05). There were more valve-related events in patients of a younger age at implantation (P = 0.02) and in those allograft valves from younger donors (P = 0.004). CONCLUSIONS: Allograft RVOT reconstruction is an adequate surgical therapy. The allograft should preferably be pulmonary. A younger age at implantation is a risk factor for allograft failure. Donor age may be a thus-far underestimated risk factor for allograft degeneration.

Adolescent↗

Subcoronary implantation or aortic root replacement for human tissue valves: sufficient data to prefer either technique?

The aortic root replacement technique with aortic allograft or pulmonary autograft might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. We explored the influence of the learning process on the incidence of reoperation and the severity of postoperative aortic regurgitation as assessed by color Doppler echocardiography. The subcoronary implantation technique was used in 81 patients, and root replacement was done in 63 patients. The first 30 patients of each group were considered as the surgeons' learning curve. Reoperations were more common in the subcoronary implantation group. After exclusion of early reoperations, the median regurgitation score based on echocardiographic examination was 0.22 in the first 30 patients from the subcoronary implantation group and 0.14 in the root replacement group. The subsequent patients from these groups had regurgitation scores of 0.20 and 0.17, respectively. Statistical analysis of these data showed no significant difference. This interim report suggests that the learning curve for the surgical procedure and the grouping of echocardiographic data influence the interpretation of follow-up studies. The superiority of either technique with regard to aortic regurgitation has yet to be proved.

Adolescent↗

Aortic root replacement with a pulmonary autograft.

A series of 42 consecutive patients with exclusively aortic root replacement using the pulmonary autograft is presented. The mean age at operation was 19.3 years (range 0.3-41.4). Two patients died in hospital (4.8%; 70% CL: 0.0-8.2). This mortality was not related to the autograft procedure. The mean follow-up time was 30 months (range 3-70; SD: 20). Late mortality consisted of two patients; in one of these severe autograft failure occurred due to chronic juvenile rheumatoid arthritis. The estimated survival rate at 4 years was 88.8% (70% CL: 83.3-94.5). Morbidity involved three patients. One had a total heart block after operation, requiring pacemaker implantation and two patients were reoperated: one for severe autograft failure due to recurrent acute rheumatic fever and the other for severe stenosis at the distal anastomosis of the pulmonary allograft. Thromboembolic complications and endocarditis were not registered. Reoperations for technical or degenerative reasons were not necessary. The estimated event-free survival rate at 4 years was 78.7% (70% CL: 71.0-86.4). Serial echocardiography (n = 28) showed a significant increase of the autograft annulus diameter of 2.9 mm (SD: 2.7). Thirty-five of the 37 patients with an autograft in situ were in NYHA class I, and 2 in class II. At last follow-up precordial color Doppler echocardiography showed moderate aortic regurgitation in one patient and no, trivial or mild aortic regurgitation in 36 patients. Stenosis of the autograft was not observed. These medium-term results are promising with respect to mortality, morbidity and functional results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Pulmonary homograft insertion after repair of pulmonary stenosis.

Although the results of intracardiac repair for pulmonary stenosis or atresia are generally good, some patients develop symptoms due to to pulmonary regurgitation and right ventricular dilatation. Implantation of a pulmonary homograft may have a beneficial effect on these symptoms. Twenty-seven patients with symptoms due to pulmonary regurgitation and right ventricular dilatation were reoperated. The indication for surgery was dyspnea in 19, arrhythmia in five and both symptoms in three patients. The arrhythmia was supra-ventricular in four, ventricular in two and both supra-ventricular and ventricular in another two patients. A cryopreserved pulmonary homograft was implanted in the right ventricular outflow tract. Mean interval between intracardiac repair and homograft implantation was 15.6 years. Mean age at homograft implantation was 23.0 years. Concomitant procedures were performed in 18 patients. There were two early deaths (7%). Replacement of the homograft was necessary in one patient, 21 months after insertion. This patient had residual pulmonary stenosis immediately after surgery. On mid-term follow up (mean 36 months) all patients with dyspnea as indication for operation improved, except one with right and left ventricular dysfunction. Only two of eight patients with arrhythmia improved. On echocardiography, pulmonary regurgitation decreased in all patients. Right ventricular dilatation decreased in only 14 patients (52%). We conclude that pulmonary regurgitation after transannular patching can be treated with implantation of a cryopreserved pulmonary homograft with acceptable mortality and low morbidity. Clinical improvement results from reduction of the right ventricular volume overload rather than from decline in right ventricular dilatation. Arrhythmia as the only indication for operation is controversial.

Adolescent↗

[Aortic valve replacement using aortic donor valves of human origin].

OBJECTIVE: To evaluate the experiences of aortic valve replacement with cryopreserved aortic allografts in the subcoronary position. DESIGN: Descriptive clinical study. SETTING: Thorax Centre of Rotterdam University Hospital. METHOD: In the period July 1988-March 1993, 68 patients (45 men and 23 women) with a mean age of 45 years underwent 69 operations. One woman was operated twice. Main criteria for aortic valve replacement by an allograft were age and endocarditis. The pathology leading to aortic valve dysfunction had been: endocarditis (38%), congenital lesions (32%), rheumatic lesions (19%), senile degeneration (7%), paravalvular leakage (3%) and an active autoimmune disease (1%). RESULTS: Hospital mortality was 4%. The mean follow-up was 22 months, with a cumulative follow-up of 126 patient years. One patient died of lung cancer during this period. Six patients needed a second operation (9%); 4 of these were among the first 15 patients operated on. One of these reoperations was necessary to treat a recurrent endocarditis. Only one other late valve-related event took place: a transient ischaemic attack 2 years postoperatively. Ninety-one per cent of the patients with an allograft in situ were in NYHA class I at their last outpatient clinic visit. The other patients were in class II. Pre-cordial color Doppler echocardiography showed no or mild aortic regurgitation in 95% of these patients. The remaining 3 patients had moderate aortic regurgitation. CONCLUSION: Aortic valve replacement with an allograft was performed with low hospital mortality. The expected advantages are greatest in young patients and patients with endocarditis; these patients, therefore, should have priority in allograft allocation.

Adolescent↗

Gradient echo MRI for measurement of the pulmonary autograft diameter after transplantation to the aortic root: validation and comparison with ultrasound.

The purpose of this study was to s the value of MRI for measurement of pulmonary autograft diameters after transplantation to the aortic root in adults. Thirty-eight adults underwent this operation. MRI and transesophageal echocardiography (TEE) were performed in 30 and 27 patients, respectively, after a mean follow-up period of 2.8 years. For internal validation of MRI, measurements at the diastolic short and long axes of the sinus level were used. Pulmonary autograft diameters were measured and compared with MRI and TEE at five different levels: the subannular region (1), annulus (2), sinus (3), sinotubular junction (4), and the distal part of the autograft (5). The correlation coefficient (r2) between long- and short-axis measurements for corresponding sinuses was .97. Diameters obtained with MRI were 1 to 3 mm larger than those obtained with TEE (P < .05), except for the annulus at systole (P > .3). Cine gradient echo MRI is an appropriate technique to evaluate pulmonary autograft diameters during follow-up. Concordance with TEE was good, apart from a systematic difference of approximately 2 mm.

Adult↗