Cardiac Catheterization and Interventional Techniques

(1)

Cardiology Department, Maria Vittoria Hospital and Department of Public Health and Pediatrics University of Torino, Torino, Italy

5.1 Cardiac Catheterization

Historically, cardiac catheterization has been a mainstay for the diagnosis of cardiac tamponade, constrictive pericarditis and cardiac tamponade. Nowadays, the widespread use of alternative non-invasive diagnostic techniques has seriously limited the role of cardiac catheterization to complex cases, where there are conflicting data from clinical evaluation and non-invasive imaging for constrictive pericarditis or restrictive cardiomyopathy or emergency/urgent settings where cardiac tamponade develops during invasive procedures (e.g. coronary angioplasty, pacemaker implantation or arrhythmias ablation) and requires immediate diagnosis and treatment [1–4].

Cardiac Tamponade

It is only rarely diagnosed by cardiac haemodymamics. Cardiac tamponade develops when cardiac filling is impaired by intrapericardial pressure exceeding intracardiac pressures, resulting in impaired ventricular filling during the entire diastolic time.

The classical haemodynamic picture includes arterial hypotension, pulsus paradoxus (see Chap. 3) and atrial pressure that is typically elevated, with prominent x descents and blunted or absent y descents (Fig. 5.1). Blunted or absent y descent is secondary to diastolic equalization of pressures in the right atrium and right ventricle and lack of effective flow across the tricuspid valve in early ventricular diastole [3].

Fig. 5.1

Hemodynamic tracing of atrial pressure in cardiac tamponade showing blunted or absent y descent (panel A) and normal conditions (panel B). RA Right Atrium, * is used to underline the changes

Constrictive Pericarditis

In constrictive pericarditis, a rigid pericardium that may be thickened or not thickened fixes the total volume of cardiac chambers, dissociates the intrathoracic pressures from intracardiac pressures and impairs diastolic filling in mid and late diastole (Fig. 5.2) [1, 3].

Fig. 5.2

Pathophysiology of constrictive pericarditis. The diastolic ventricular filling is impaired in mid- and late diastole; thus, the early diastolic filling is quick and suddenly halted by the rigid pericardium in mid-diastole

The main differential diagnosis is with restrictive cardiomyopathy (rCMP). In this pathological condition, diastolic filling is impaired because of a disease of the myocardium and not the external envelope; thus, diastolic dysfunction is present and primarily affects the left ventricle, and high filling pressures are recorded in all cardiac chambers; moreover there is no dissociation of intrathoracic pressures and intracardiac pressures.

The classical haemodynamic criteria for the differentiation of rCMP from constrictive pericarditis include [1, 3, 4]:

LV end-diastolic pressure (LVEDP) exceeds RV end-diastolic pressure (RVEDP) by 5 mmHg or more.

In RV, the RVEDP is less than 1/3 of systolic pressure.

Pulmonary artery systolic pressure is greater than 50 mmHg.

In addition in constrictive pericarditis, cardiac catheterization shows:

Dip and plateau pattern of ventricular pressure curves (Fig. 5.3) during early diastole and rapid x and y descents of atrial pressures curves (as can be seen in rCMP)

Fig. 5.3

Dip and plateau pattern of constrictive pericarditis (see text for explanation)

Dissociation of intracavitary and intrathoracic pressures with inspiratory decrease of LV pressure and increase of RV pressure with enhancement of ventricular interdependence and discordant changes in LV and RV pressures during respiration (only in constrictive pericarditis)

This respiratory reciprocal changes of ventricular pressures can be quantified using a systolic area index (SAI) that has been proposed by the Mayo Clinic investigators (Fig. 5.4) [5].

Fig. 5.4

Systolic area index (SAI). A SAI ratio >1.1 has 97 % sensitivity and 100 % predictive accuracy to identify patients with constrictive pericarditis (this ratio has been validated in a study with surgically proven constrictive pericarditis)

5.2 Pericardiocentesis

Pericardiocentesis is the interventional technique to drain pericardial fluid by a percutaneous route. It has been first developed as blinded or ECG-guided technique by a subxiphoid approach (Fig. 5.5). Nowadays, due to the high possible complication risk, pericardiocentesis should be no more blinded or ECG guided, and essentially it can be performed by echocardiographic guidance to assess the place where the size of pericardial effusion is largest and closest to the thoracic surface or by fluoroscopic guidance especially when cardiac tamponade occurs in the cath lab as complication of a diagnostic or therapeutic interventional technique [4, 6].