# Establishment of a Risk Scoring Model for Perioperative Unex-Plained Shock during Percutaneous Coronary Intervention for the Treatment of Chronic Total Occlusion

## TL;DR

This study identifies risk factors for unexpected shock during a heart procedure called CTO PCI and creates a model to predict it.

## Contribution

A novel risk-scoring model is developed to predict unexplained perioperative shock during CTO PCI procedures.

## Key findings

- Unexplained shock occurred in 4.8% of patients undergoing CTO PCI.
- The risk model achieved an unbiased C-index of 0.859, indicating strong predictive accuracy.
- Key predictors included baseline systolic pressure, heart rate, hemoglobin, procedure duration, J-CTO score, and retrograde approach use.

## Abstract

Several complications can contribute to the risk of shock
during the chronic total occlusion (CTO) percutaneous coronary intervention (PCI)
procedure. However, some patients that develop shock do not exhibit any apparent
complications, and few studies to date have discussed the risk of unexplained
perioperative shock in patients undergoing CTO PCI. Accordingly, this study was
designed with the goal of defining perioperative risk factors linked to the odds
of unexplained shock during CTO PCI.

In total, this study
analyzed data from 924 patients that underwent CTO PCI without any in-hospital
complications from January 2016–August 2021. Cardiologists collected data
pertaining to patient clinical characteristics, laboratory findings, angiographic
findings, and procedural characteristics. Patients were separated into two groups
based upon whether or not they experienced perioperative shock. The relationship
between specific variables and perioperative shock incidence was assessed via a
multivariable stepwise logistic regression approach. A risk-scoring nomogram was
then designed for use as a tool to guide patient risk assessment efforts during
PCI procedural planning.

Overall, 4.8% of these patients
(44/924) experienced unexplained perioperative shock. Independent predictors
associated with unexplained shock during CTO PCI included baseline systolic
pressure (odds ratio (OR) 0.968, 95% confidence interval (CI): 0.945–0.991), baseline heart rate (OR 1.055, 95%
CI: 1.020–1.091), baseline hemoglobin (OR 0.970, 95% CI: 0.947–0.994),
procedure duration (OR 1.008, 95% CI: 1.002–1.015), J-CTO score (OR 1.521, 95%
CI: 1.021–2.267), and use of a retrograde approach (OR 3.252, 95% CI:
1.426–7.415). The unbiased C-index estimate was 0.859, and this model exhibited
excellent calibration.

The risk of unexplained shock is an
important consideration for clinicians performing the CTO PCI procedure. These
analyses revealed unexplained shock risk to be independently related to lower
baseline systolic pressure, higher baseline heart rate, lower baseline
hemoglobin, more procedure time, higher J-CTO score, and more use of a retrograde
approach.