RV-BIOPSY PROTOCOL FOR ARVC

The histological diagnosis of arrhythmogenic right ventricular dysplasia (ARVC) is made from histological slides obtained from right ventricular endomyocardial biopsy samples. Typical histological features of ARVC include myocardial atrophy with replacement by fibrous and/or fatty tissue interspersed with surviving strands of hypertrophied myocytes. These changes affect primarily the right ventricular free wall whereas the interventricular septum is usually spared. Left ventricular involvement may be present, particularly in advanced stages of ARVC.

Because the septum is usually spared and because tissue abnormalities may be localized, there is significant sampling error if standard septal sampling is performed.

Predilection areas in the subtricuspid (basal inferior), apical and outflow tract areas of the right ventricular free wall. Therefore, biopsies should be sampled at the myocardial border of the RV free wall and the septum at the areas of predilection or documented contraction abnormalities.

The following protocol for RV biopsy is designed to provide a description of RV biopsy technique in ARVC for the use within the Multidisciplinary Study of ARVC. Biopsy samples are placed in formalin, embedded in a paraffin block, and sent to the Pathology Core-Lab.

A)Subject Preparation

Patient informed consent

  • Biplane digital cath lab preferred
  • Biopsy sampling is performed during right heart catheterisation

B)Venous Approach and RV Access

See also “Angiography Protocol for ARVC”

Femoral vein approach: RV access with long sheath (8-9F) positioned in RV inflow tract.

  • Jugular vein approach: long sheath in RV usually not required.

C)Technique of RV biopsy in ARVC

  • Record RV and RA pressures prior to biopsy sampling.
  • Use bioptome with medium sized jaws.
  • Create a 70-90° smoothe curve at distal end (5-7 cm) of bioptome (for better steerability).
  • Use biplane views for sampling (i.e. 30° RAO and 60° LAO views)
  • Target sampling to abnormal areas (echo, angio) and predilection areas (RVO, apex, basal inferior walls)
  • Take samples at the myocardial border of RV free wall and septum (but not strictly septal). To do this, direct bioptome half-way posteriorly in 60° LAO view.
  • Open bioptome jaws just outside the long sheath, then approach RV wall with open jaws (never open the jaws within the trabecular system: distension may cause perforation!)
  • Close jaws when good contact with targeted area of RV wall is achieved.
  • Take sample by withdrawal of closed bioptome into long sheath. Slight resistance is normal.
  • Never enforce sampling in case of strong resistance at withdrawal (risk of perforation!). In that case, let loose by opening the jaws and make new attempt of sampling at neighbouring site.
  • Take 5 samples of sufficient size (see pathology Core-Lab)
  • Repeat RV and RA pressure recording after sampling is finished and remove long sheath from RV.

D)RV Biopsy Samples (check with Pathology Core Lab)

  • Place samples into formalin
  • Embed samples into paraffin block
  • Send material to Pathology Core-Lab according to specifications given by Pathology Core Lab