R

Ralf J. Holzer

University of California, Davis

ORCID: 0000-0003-2915-3724

Publishes on Congenital Heart Disease Studies, Cardiac Valve Diseases and Treatments, Central Venous Catheters and Hemodialysis. 169 papers and 5.4k citations.

169Publications
5.4kTotal Citations

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Top publicationsby citations

Radiation safety program for the cardiac catheterization laboratory
Charles E. Chambers, Kenneth A. Fetterly, Ralf J. Holzer et al.|Catheterization and Cardiovascular Interventions|2011
Cited by 304Open Access

The Society of Cardiovascular Angiography and Interventions present a practical approach to assist cardiac catheterization laboratories in establishing a radiation safety program. The importance of this program is emphasized by the appropriate concerns for the increasing use of ionizing radiation in medical imaging, and its potential adverse effects. An overview of the assessment of radiation dose is provided with a review of basic terminology for dose management. The components of a radiation safety program include essential personnel, radiation monitoring, protective shielding, imaging equipment, and training/education. A procedure based review of radiation dose management is described including pre-procedure, procedure and post-procedure best practice recommendations. Specific radiation safety considerations are discussed including women and fluoroscopic procedures as well as patients with congenital and structural heart disease.

Transcatheter closure of postinfarction ventricular septal defects using the new Amplatzer muscular VSD occluder: Results of a U.S. Registry
Ralf J. Holzer, David T. Balzer, Zahid Amin et al.|Catheterization and Cardiovascular Interventions|2004
Cited by 220

The objective of this study was to assess the immediate and mid-term results of transcatheter closure of postinfarct muscular ventricular septal defects (VSDs) using the new Amplatzer postinfarct muscular VSD device (PIMVSD). Ventricular septal rupture occurs in 0.2% of myocardial infarcts and remains associated with very high morbidity and mortality. Data were prospectively collected for 18 patients who underwent attempted device closure of postinfarction VSDs between 2000 and 2003. Five patients underwent the closure in the acute phase (within 6 days from the infarct); the remaining patients underwent closure on day 14-95 after the diagnosis of the infarct. Outcome parameters included procedural success, evidence of residual shunts on echocardiography, and occurrence of procedure-related complications. The procedure was successful in deploying a device across the VSD in 16 of 18 patients. The 30-day mortality was 28%. Eleven patients are still alive and have been followed up for a median of 332 days. Two patients required a second procedure to close a residual VSD. At the most recent outpatient follow-up, the VSD was completely closed in two patients, six patients had a trivial or small residual shunt, and two patients had a moderate residual shunt. We conclude that percutaneous device closure of postinfarction VSDs using the Amplatzer PIMVSD occluder appears to be safe and effective. Further trials are required to assess long-term efficacy and compare the results with those of surgical closure.

Transcatheter closure of perimembranous ventricular septal defects using the amplatzer membranous VSD occluder: Immediate and midterm results of an international registry
Ralf J. Holzer, Jo de Giovanni, Kevin Walsh et al.|Catheterization and Cardiovascular Interventions|2006
Cited by 217

OBJECTIVE: To report the immediate and midterm results of transcatheter closure of perimembranous ventricular septal defect (PmVSD) using the Amplatzer membranous VSD occluder (AMVSD). METHODS: Between April 2002 and August 2004, 100 patients underwent an attempt of percutaneous device closure of PmVSD using the AMVSD in 24 international centers. The median age was 9.0 years (0.7-58 years) and the median weight was 27.5 kg (7-121 kg). RESULTS: A device was successfully deployed in 93/100 (93%) patients. Reasons for procedural failure were an increased gradient across the left ventricle outflow tract in one patient, aortic regurgitation in 2 patients, and inability to securely position the device in 4 patients. The median VSD size by TEE was 7.0 mm (1.5-13 mm), median device size 10 mm (4-16 mm) and median fluoroscopy time 22.1 min (8.9-96.0 min). Weight below 10 kg (P = 0.0392), inlet extension of the VSD (P = 0.0139) and aortic cusp prolapse into the VSD (P = 0.0084) were significantly associated with a lower procedural success. Patients have been followed up for a median of 182 days (1-763 days). There were no procedure-related deaths. Complications were encountered in 29/100 (29%) patients, including rhythm or conduction anomalies in 13 patients (two with complete heart block requiring permanent pacemaker implantation), new or increased aortic (9 patients) or tricuspid (9 patients) regurgitation, most of which were classified as trivial or mild. Patients with a weight below 10 kg had a significantly higher incidence of adverse events than patients with a weight above 10 kg (58.3% versus 25.0%, P = 0.0285). Immediately after device release complete closure of the defect was present in 54/93 (58.1%) patients, increasing to 46/55 (83.6%) patients at 6-months follow-up (P = 0.0012). Left ventricle end-diastolic diameter decreased from a median of 44 mm prior to device closure to a median of 39 mm at 6-months postprocedure (P = 0.0015). CONCLUSION: Closure of PmVSDs using the AMVSD occluder is safe and effective. However, longer follow-up period is warranted prior to the wide spread use of this device.