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Biomedical subjects

P N Ruygrok

Publications and source records attributed to P N Ruygrok.

At least 19 recordsLinked to original sources
PubMed2005

Transcatheter closure of a complex postmyocardial infarction ventricular septal defect after surgical patch dehiscence.

Ventricular septal defect (VSD) complicating acute myocardial infarction is a rare but serious event carrying a high mortality. Residual shunting after emergency surgical repair is common, adversely affects prognosis and can necessitate reoperation. We describe the successful transcatheter VSD closure with the Amplatzer occluder in a 75-year old man after earlier emergency surgical repair of a VSD complicating an acute myocardial infarction. The technique and positioning of the device in a tortuous infero-apical VSD are described.

Aged↗
PubMed2005

Percutaneous closure of patent foramen ovale.

AIM: To review the safety and efficacy of percutaneous closure of patent foramen ovale (PFO) in symptomatic patients without the use of general anaesthesia or echocardiographic guidance. METHOD: All patients accepted for percutaneous PFO closure by our service from August 2002 to August 2004 were included. Patient demographics and clinical information were obtained from clinical records and by telephone interview. Follow-up outcomes recorded were recurrence of systemic thromboembolism, residual shunt, and change in pattern of migraines. RESULTS: Forty consecutive adult patients, of whom 19 (48%) had an atrial septal aneurysm (ASA), underwent PFO closure using the Amplatzer occluder device with fluoroscopic guidance alone. Their mean age was 45 +/- 10 years (range 23-63 years) and 24 (60%) were male. The indications for closure were ischaemic stroke (n = 26), transient ischaemic attack (TIA) (n = 8), both stroke and TIA (n = 2), refractory hypoxia (n = 2), platypnoea-orthodeoxia (n = 1) and severe migraine with seizures (n = 1). Twenty patients suffered a single neurological event and 16 suffered >1 event, including six with only radiographic evidence of >1 event. Mean procedure time was 17.7 +/- 9.6 min and fluoroscopy time was 6.7 +/- 7.3 min. Implanted device sizes were 18 mm (n = 1), 25 mm (n = 37) and 35 mm (n = 2). In 33 patients, the procedure was performed as a day-case. No complications were encountered. No further neurological events occurred in 39 patients at a mean follow-up time of 11 +/- 7 months (3-25 months) nor was a significant shunt detected in the 34 who underwent follow-up echocardiography. CONCLUSIONS: Percutaneous closure of PFO with or without ASA, under local anaesthesia and without echocardiographic guidance, is a safe and effective procedure which can be performed as a day-case. This has now become our standard clinical practice.

Adult↗
PubMed2004

Transplant "twins": the experience of sharing transplanted thoracic organs from the same donor.

BACKGROUND: Many thoracic transplant recipients who receive organs from the same donor share facilities for 3 months, and are aware that they have received organs from the same donor. METHODS: A confidential questionnaire including open and closed questions assessed relationships between "twins" and the experience of having a twin. The Significant Others Scale assessed social support. Of 141 heart and 58 lung transplants, 25 pairs of transplant twins were identified. Questionnaires were sent to the 32 surviving twins. RESULTS: Twenty-six twins responded; 17 had received a heart and nine a lung. The 17 men and 9 women had a mean age of 51 years. Eighteen respondent's "twins" remained alive at the time of participation and eight had died. Sixty-six percent of the both- twin alive group and 43% of one-twin alive group felt they had a special bond with their twin, different from the other relationships that they have experienced. Fifty-six percent of the both-twin alive group and 43% of one-twin alive group felt having a twin enriched their transplant experience. Transplant twins rated social support last behind: the transplant support personnel; close family members; other transplant recipients; and good friends and general practitioners, both in levels of ideal and actual support. Transplant twins showed the largest discrepancy between levels of ideal and actual support than any other individual ranked. CONCLUSIONS: Being a transplant twin is a special experience that generally enriches the overall transplant experience but having a transplant twin, does not appear to enhance the amount of social support.

Cadaver↗
PubMed2004

Planned pregnancy in a heart transplant recipient.

Solid organ transplantation often leads to the return of fertility in recipients. In females of childbearing age this can be accompanied by a desire to have children. The present paper discusses a planned pregnancy in a heart transplant recipient and outlines important -management issues. These principles of management can be applied to most solid organ transplant recipients.

Adult↗
PubMed2003

Rapamycin in cardiovascular medicine.

The cellular action of rapamycin (sirolimus), a natural fermentation product produced by Streptomyces hygroscopicus, is mediated by binding to the FK506 binding protein. By inhibiting a kinase known as the target of rapamycin, it restricts the proliferation of smooth-muscle cells by blocking cell-cycle progression at the G1/S transition. The finding that rapamycin possesses both anti-proliferative and antimigratory activity suggests that it could contribute to the control of arterial re-narrowing after percutaneous intervention and control the vascular manifestations of chronic rejection in transplanted hearts. The first clinical trials of implantation of rapamycin- coated stents in obstructive coronary artery lesions have been reported and, in selected patient groups, it appears that the restenosis process has been abolished. Studies are underway to establish the benefits of rapamycin-coated stents in day-to-day interventional practice, including small vessels, long lesions and patients with multivessel disease. With the addition of novel antiplatelet agents and delivery systems, it is possible that the two major limitations of percutaneous coronary intervention - restenosis and stent thrombosis - will be overcome. Cardiac graft loss due to intimal hyperplasia and accelerated atherosclerosis remains the major limitation to long-term survival following cardiac transplantation. Animal studies of rapamycin have suggested that this process can be reduced or abolished. Human studies of the efficacy of rapamycin in preventing both acute rejection and allograft arterial disease are in progress. Concerns regarding toxicity, carcinogenicity, delayed healing and endothelialization remain. As with any new agent or technology, we must remain vigilant to late adverse side-effects.

Coated Materials, Biocompatible↗
PubMed2001

Clinical and angiographic factors associated with asymptomatic restenosis after percutaneous coronary intervention.

BACKGROUND: Angiographic restenosis after percutaneous coronary interventional procedures is more common than recurrent angina. Clinical and angiographic factors associated with asymptomatic versus symptomatic restenosis after percutaneous coronary intervention were compared. METHODS AND RESULTS: All patients with angiographic restenosis from the BENESTENT I, BENESTENT II pilot, BENESTENT II, MUSIC, WEST 1, DUET, FINESS 2, FLARE, SOPHOS, and ROSE studies were analyzed. Multivariate analysis evaluated 46 clinical and angiographic variables, comparing those with and without angina. The 10 studies recruited 2690 patients who underwent percutaneous revascularization and 6-month follow-up angiography (86% of those eligible). Restenosis (>/=50% diameter stenosis) occurred in 607 patients and was clinically silent in 335 (55%). Male sex (P=0.008), absence of antianginal therapy with nitrates (P=0.0002) and calcium channel blockers (P=0.02) at 6 months, greater reference diameter after the procedure (P=0.04), greater reference diameter at follow-up (P=0.004), and lesser lesion severity (percent stenosis) at 6 months (P=0.0004) were univariate predictors of asymptomatic restenosis. By multivariate analysis, only male sex (P=0.04), greater reference diameter at follow-up (P=0.002), and lesser lesion severity at 6 months (P=0.0001) were associated with restenosis without angina. CONCLUSIONS: Approximately half of patients with angiographic restenosis have no symptoms. The only multivariate predictors of silent restenosis at 6 months were male sex, greater reference diameter at follow-up, and lesser lesion severity on follow-up angiography.

Angioplasty, Balloon, Coronary↗
PubMed2001

Outcome following heart transplantation in Maori and Polynesian patients: a comparison with European New Zealanders.

AIM: To compare demographic, clinical and outcome data of Maori and Polynesian with New Zealand European heart transplant patients. METHODS: A retrospective analysis was made of data from the 104 patients who underwent heart transplantation at Green Lane Hospital over a period of twelve years, of whom 79 were European, 23 Maori/Polynesian, and two Asian. Clinical characteristics, blood group, HLA matching and outcomes of recipients were compared. RESULTS: There was no significant difference in age and gender between the two groups. Maori and Polynesian patients were heavier, had a greater body mass index and were more likely to have rheumatic heart disease than their European counterparts. Maori/Polynesian patients were predominantly blood group A, whilst European patients were mainly group O. The waiting time for a donor heart was similar in both groups. There was no significant difference in number of rejection episodes and survival. CONCLUSIONS: Green Lane Hospital has the largest international experience of heart transplantation in Maori and Polynesian patients. Although there are some differences in clinical profile, outcome in terms of rejection episodes and survival is similar in the two groups.

Adolescent↗
PubMed2001

5 French guide catheters for percutaneous coronary intervention: a feasibility study in 100 consecutive patients.

Percutaneous coronary intervention using smaller-diameter guide catheters may have a favorable impact on groin complications, mobilization time, hospital stay, and contrast use. This prospective registry study assessed the feasibility of routine stent delivery through 5 Fr guide catheters. Of the 100 consecutive patients, 5 Fr guided intervention was attempted in 84 and was successful in all but 2 patients who had chronic complete occlusions. Reasons for not selecting a 5 Fr guide were planned kissing balloons (eight), directional coronary atherectomy (one), and no suitable 5 Fr guide in stock (seven). There was no stent dislodgment, need to change to a larger-caliber guide, or inadequate contrast opacification. When necessary, guide support was achieved by deep-vessel intubation, which was not associated with vascular damage. The only adverse sequelae were non-Q-wave myocardial infarctions in two patients. Coronary artery stenting using 5 Fr guide catheters is feasible and applicable to most patients.

Adult↗
PubMed2000

Coronary angioplasty in New Zealand 1995-1998: a report from the National Coronary Angioplasty Registry.

AIMS: To report coronary angioplasty data collected by the New Zealand Coronary Angioplasty Registry from 1995-1998. METHOD: Information on all patients undergoing attempted coronary angioplasty in eight New Zealand institutions was recorded on datasheets at the time of, or soon after, the procedure. These were forwarded to the registry at Green Lane Hospital. RESULTS: Over the four-year period, 8395 angioplasty procedures were performed by 26 cardiologists in eight coronary interventional facilities, with a procedural success rate of 94%. Procedural numbers grew steadily, with 55% more coronary angioplasties performed in 1998 than in 1995 (p = 0.02). The New Zealand national angioplasty rate, which rose from 459/million population in 1995 to 684/million in 1998, remains lower than that of Australia and Western European countries. Excluding those that underwent angioplasty for acute myocardial infarction, the number of peri-procedural deaths was similar, with six in 1995 and four in 1998 (p = 0.30), and the requirement for emergency bypass surgery fell from 22 cases in 1995 to three in 1998 (p < 0.001). The use of stents increased dramatically, with 85% of patients receiving a stent in 1998, compared with 23% in 1995 (370% increase, p < 0.001). This was associated with a reduction in the number of patients requiring repeat percutaneous interventions for restenosis (10.7% in 1995 to 6.4% in 1998, p < 0.001). CONCLUSION: There has been a steady growth in the numbers of patients with coronary artery disease treated by coronary angioplasty, and in the number treated by intracoronary stents from 1995 to 1998. The need for urgent coronary bypass surgery has fallen. Continued submission of complete and accurate data to the coronary angioplasty registry is vital for ongoing audit.

Adult↗
PubMed2000

Stent longitudinal flexibility: a comparison of 13 stent designs before and after balloon expansion.

Longitudinal flexibility is an important property of coronary stents, facilitating delivery and allowing the expanded stent to conform to vessel contour. Subjective descriptions of flexibility abound, but there are few independent quantitative data to aid stent selection. A three-point bend test was employed to measure stiffness, the reciprocal of flexibility, for 13 stent designs in the unexpanded (bare) state, then after expansion with a 3.5-mm balloon. For eight of the designs, stiffness of the proprietary stent/balloon delivery system was also measured. In the unexpanded state, there was a wide spread of stiffness, which ranged from 0.5+/-0.2 to 91.5+/-10.0 g force/mm, depending on design. Stiffness was least for the coil (Wiktor and Crossflex) and hybrid (AVE GFX and Bard XT) designs. The MultiLink was the most flexible and the Crown the stiffest of the slotted tube designs. All stents became stiffer upon expansion. For most manufacturer-mounted stents, the delivery balloon was the main determinant of stent/balloon delivery system stiffness. Manufacturer-mounted stent profile ranged from 1.15+/-0.11 mm for the Jostent to 1.53 +/- 0.05 mm for the MultiLink system. Independent quantitative assessment of characteristics such as flexibility and profile should aid rational comparison of stent designs.

Equipment Design↗
PubMed2000

A randomized study of direct coronary stent delivery compared with stenting after predilatation: the NIR future trial. On behalf of the NIR Future Trial Investigators.

This randomized trial compared a strategy of direct stenting without predilatation (n = 39) with conventional stenting with predilatation (n = 42) in patients with suitable lesions in native vessels > or = 2. 5-mm diameter to be covered by either a 9- or 16-mm-length NIR Primo stent. Equipment cost [mean (median) +/- SD] was less in those with direct stenting [$1,199 (979) +/- 526] than in those with predilatation [$1,455 (1,285) +/- 401, P < 0.001]. There was no significant difference in contrast use or fluoroscopy time. Procedural time was shorter in the direct stenting group. The clinical outcome at 1 month was satisfactory in both groups. In selected patients, a strategy of direct stenting is feasible, costs less, and is quicker to perform than the conventional strategy of stenting following predilatation.

Adult↗
PubMed1999

Cardiac allograft vasculopathy: the green lane hospital experience 1987-1998.

AIMS: To determine the prevalence of cardiac allograft vasculopathy in heart transplant recipients at Green Lane Hospital and to examine potential risk factors for vasculopathy. METHODS: We retrospectively reviewed the coronary angiograms of all cardiac transplant recipients. Angiography was usually performed one, two and five years after operation. The diagnosis of allograft vasculopathy was made if there was any evidence of coronary artery disease. Patients' medical records were reviewed for potential risk factors. RESULTS: Ninety-one patients underwent cardiac transplantation between December 1987 and March 1998. One year survival was 87%. Angiographic evidence of coronary disease was present in 30 patients and in three patients coronary lesions were first identified at post mortem. Vasculopathy was present in 25%, 35% and 61% of patients at one two and five years following transplant. Donor-acquired lesions could not be excluded as few patients had immediate postoperative angiograms for comparison. Five late deaths have been due to vasculopathy. Recipient age, race, donor age and ischaemic time were similar for those with and without vasculopathy. Frequency or severity of acute rejection episodes, cytomegalovirus infection, lipid profiles, diabetes and hypertension were not significantly different in patients with vasculopathy. CONCLUSION: Cardiac allograft vasculopathy is a common finding after heart transplantation. No definite risk factors were identified in this patient group.

Adult↗
PubMed1999

Does angiography six months after coronary intervention influence management and outcome? Benestent II Investigators.

OBJECTIVES: This study was performed to assess whether angiography six months after coronary balloon angioplasty or stent implantation has an influence on clinical management and one-year outcome. BACKGROUND: The Benestent II study randomized 827 patients to balloon angioplasty or stent implantation. A subrandomization was undertaken allocating patients to six-month clinical follow-up (CF) or clinical and angiographic follow-up (AF). METHODS: Seven hundred and six patients (349 CF and 357 AF) had no intercurrent angiography, so that restenosis and disease progression elsewhere remained unknown until the time of six-month follow-up. These two groups, which were well matched at enrolment, were compared with respect to symptoms, medication and major cardiac events defined as death, myocardial infarction and need for revascularization at six and 12 months. RESULTS: At six-month follow-up, 53 (15%) of the CF and 76 (21%) of the AF patients had stable angina (p = 0.041), while 5 (1%) and 4 (1%) had symptoms of unstable angina. At 12-month follow-up, 44 (13%) patients in both groups had stable angina, and only 1 patient in the CF group had unstable angina. Seventy-seven patients (27 CF and 50 AF; p < 0.01) had major cardiac events between 6 and 12 months. Of the 349 patients in the CF group, 21 underwent repeat percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery between 6 and 12 months, compared with 44 of the 357 patients in the AF group (relative risk 2.05 [1.24 to 3.37], p = 0.003). CONCLUSIONS: Patients who had AF six months after balloon angioplasty or stent implantation experienced more repeat revascularization procedures than those who had CF. They also had significantly more angina at six-month follow-up but this may be due to bias.

Angina Pectoris↗
PubMed1999

Stent deformation following simulated side-branch dilatation: a comparison of five stent designs.

We aimed to determine the effects of simulated stent side-branch dilatation and subsequent redilatation of the central lumen. Following coronary stent implantation it may be necessary to dilate through the side of a stent to maintain branch patency. Branch dilatation through the side of 3.5-mm-diameter stents (AVE GFX, beStent, Crown, MultiLink, and NIR) was simulated in a plexiglass phantom using 2.5-, 3.0-, 3.5-, and 4.0-mm balloons. In further experiments, the main lumen was redilated with a 3.5-mm balloon after 3.0-mm side-branch dilatation. Thereafter, a 3.5-mm central and a 3.0-mm side-branch balloon were simultaneously inflated ("kissing balloons"). The larger the balloon size used for side-branch dilatation, the greater the distortion of the stent immediately distal to the side-branch, which for a 4.0-mm balloon ranged from 36% +/- 2% (Crown) to 65% +/- 6% (NIR). Central lumen redilatation or kissing balloons abolished this stenosis with little reduction of the side-lumen diameter. The main stent lumen compromise caused by side-branch dilatation can be abolished by main-lumen redilatation or by kissing balloons.

Catheterization↗