Objective: To develop a new score (CATH-score) for predicting intra-procedural risk in patients undergoing CT-guided percutaneous needle pulmonary biopsy.
Patients and methods: 100 CT-guided lung biopsies performed with a 18 Gauge (G) needle (Pilot Group) were reviewed to analyse patient-, lesion- and procedure-related variables to identify risk factors for procedural complications (pneumothorax and parenchymal bleeding) and diagnosis failure. A scoring system for predicting complications and choosing the right needle (16 G, 18 G, 21 G) was developed using risk factors weighting and prospectively applied to 153 consecutive biopsies (CATH-score Group); complications and diagnostic rates obtained were compared with a group of patients (Control Group) that underwent lung biopsy; in this group of patients the choice of the calliper of the needle was based on the operator experience.
Results: lesion diameter (p=0.03), central location of lesion (p=0.02), centrilobular emphysema (p=0.04) and trans-pulmonary needle route (p=0.002) were associated with a higher complications rate in Pilot Group and were selected as risk factors to include in the CATH-score definition. Risk factors "cut-off" values were identified (Receiver Operating Characteristics curves) and risk-stratification groups were classified as follows: low (16 G, score 1), intermediate (18 G, score 2), and high procedural risk score (21 G, score 3). CATH-score usage limited complications rate despite a higher number of 16 G needle employed, with a diagnostic performance rising respect to Control Group.
Conclusions: CATH-score seems to be a valuable tool for predicting the risk of complications and choosing the right needle, in order to increase diagnostic performance in patients undergoing TTNA.