Left Ventriculography and Aortography



Left Ventriculography and Aortography


Mateen Akhtar

Frederick A. Heupler Jr.



Left ventriculography provides important anatomic and functional information that supplements coronary angiography. Left ventriculography allows assessment of left ventricular systolic function, degree of mitral regurgitation, and the presence/location of wall motion abnormality or ventricular septal defect (Table 5-1). Ventriculography should not be performed when a patient is hemodynamically unstable. Additional contraindications are listed in Table 5-2.


Preparation

Single-plane ventriculography is performed in most catheterization laboratories. Some operators prefer biplane ventriculography since it can provide more information about ventricular anatomy and function. Biplane ventriculography has limitations such as costly angiographic equipment, additional radiation exposure to both operator and patient, and longer angiographic setup time.

The Medrad powered flow injector is connected to extension tubing and loaded with contrast. During this process, air bubbles should be purged from the injector. Once appropriate pressure measurements have been obtained, the pigtail catheter is connected to extension tubing from the power injector via a blood-contrast interface to minimize the risk of air embolism with left ventriculography. Usually the left ventricular cavity is adequately visualized with 30 to 50 mL of contrast.








Table 5-1 Left Ventriculography: Indications









Assess global left ventricular systolic function and regional wall motion


Assess severity of mitral regurgitation


Identify and assess muscular and membranous ventricular septal defects










Table 5-2 Left Ventriculography: Contraindications

















Critical left main disease


Critical aortic stenosis


Fresh intracardiac thrombusa


Contrast media reaction


Tilting-disc aortic prosthesis


Decompensated heart failure and/or renal failure


a Because sessile thrombi more than 6 months old have a lower risk of dislodgement, some operators will proceed with ventriculography in this circumstance.


The parameters listed in Table 5-3 can serve as a baseline when deciding on the rate and volume of contrast injection. Certain patient characteristics and clinical settings will influence these settings. For instance, higher volumes of contrast dye (i.e., 50-60 mL) may be necessary to completely opacify the left atrium in patients with severe mitral regurgitation. Higher rates of contrast injection may be necessary in patients with increased cardiac output or dilated left ventricular cavity. Conversely, patients with smaller ventricular cavities such as elderly females or those with hypertensive heart disease may need only 30 to 36 mL of contrast dye for adequate imaging. All patients with hemodynamically significant valvular disease, left ventricular dysfunction, or elevated left ventricular end-diastolic pressure (LVEDP) should receive nonionic contrast for ventriculography.


Entering the Ventricle

The catheter most commonly used for ventriculography is an angled pigtail catheter. The distal segment of this catheter should be angled 145° to 155° in order to facilitate passage into the left ventricle while simultaneously preventing the endhole from contacting the endocardium, thereby reducing the risk of endocardial staining. The multiple side holes help dissipate the pressure of rapid power contrast injection and prevent excessive catheter movement.








Table 5-3 Standard Settings for Left Ventriculography















Rate of rise


0-0.4 sec


Rate of injection


10-15 mL/sec


Volume of injection


30-40 cc


Maximum pressure


600-700 psi



The pigtail catheter is advanced over a 0.035-in J-tipped wire to a position in the ascending aorta just superior to the aortic valve. The tip should be pointed toward the orifice of the valve and the catheter rotated so that the pigtail loop resembles a “6.” In this position, gently advancing the catheter will usually push it across the valve orifice and into the ventricle.

Occasionally, the pigtail catheter will prolapse into the ventricle while the pigtail remains in the ascending aorta. Slowly advancing the guidewire through the terminal portion of the catheter should provide enough additional support to allow entry into the ventricle. Once in the ventricle, the tip of the pigtail should be positioned in the midcavity avoiding contact with the papillary muscles and mitral valve (Figure 5-1).






Figure 5-1 30° RAO ventriculogram demonstrating ideal placement of the pigtail catheter in the ventricular midcavity. The most common reasons for ectopy during ventriculography are contact of the catheter with either the apex or the septum. Gentle counterclockwise rotation and/or pullback of the catheter should eliminate the ectopy.



Once the catheter is stabilized within the left ventricle, it is connected to the pressure manifold, flushed, and used to record intraventricular pressures. Systolic pressure is typically recorded on a 200-mm Hg scale, while LVEDP is best appreciated on a 40-mm Hg scale. Markedly elevated LVEDP (>30 mm Hg) usually precludes left ventriculography. Administration of sublingual or intravenous nitroglycerin may reduce LVEDP to a more acceptable level.

In patients with compromised left ventricular systolic function, elevated LVEDP, or reduced creatinine clearance, a hand-injection left ventriculogram using digital subtraction angiography (DSA) may be preferred since only 10 mL of contrast is needed. Patients should be instructed to cease respiration and avoid any motion during cine acquisition in order to minimize artifact.


Jul 8, 2016 | Posted by in CARDIAC SURGERY | Comments Off on Left Ventriculography and Aortography

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