Transradial Measurement of Transvalvular Pressure Gradient in the Setting of Mechanical Aortic and Mitral Valve Prostheses Using a Coronary Fractional Flow Reserve Guidewire

Abstract: Accurate measurement of transvalvular pressure gradients is essential to comprehensively evaluate whether mechanical prosthetic valves are functioning normally. Direct measurements can be technically complicated, traditionally requiring direct, transapical puncture in the setting of both aortic and mitral mechanical valve prostheses. Very few case reports have proposed the use of guidewires indicated for coronary fractional flow reserve assessment to evaluate the transvalvular pressure gradients and hemodynamic status of patients with both aortic and mitral valve mechanical prostheses. We present one such case of a 59-year-old male with history of rheumatic heart disease and double mechanical valve replacements of the aortic and mitral valves presenting with contradictory clinical signs and non-invasive testing evidence of decompensated congestive heart failure and possible dysfunction of a mechanical, bi-leaflet aortic valve prosthesis. The use of a low-profile, intracoronary guidewire with a pressure transducer near the distal tip indicated for coronary fractional flow reserve determination proved very useful to answer this important question. Additionally, we report the first case of the use of this technology for this purpose via the radial artery access approach. 

J INVASIVE CARDIOL 2012;24:72-73

Key words: hemodynamic assessment, prosthetic valve complications, transvalvular pressure gradient

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Case Report

A 59-year-old gentleman with history of rheumatic heart disease, mechanical valve replacements at both the mitral and aortic positions 16 years prior, and then repeat mechanical aortic valve replacement due to severe paravalvular leak 2 years later, presented to us with progressively worsening shortness of breath, weakness, and dyspnea on exertion over the course of 2 months.

Physical exam was remarkable for stable vital signs without jugular venous distention or significant crackles on lung exam, but the cardiac exam was significant for audible clicks of the mechanical valves as well as a loud, systolic ejection murmur. Transthoracic and transesophageal echocardiograms revealed a malfunctioning mechanical aortic valve of bi-leaflet type with only one mobile disk and elevated systolic gradient with a peak jet velocity of 5.2 m/s and an estimated peak instantaneous gradient approximating 110 mm Hg. Because the patient’s symptoms and physical exam findings somewhat contradicted the very high jet velocity and pressure gradients from the non-invasive testing, suspicion was raised of an overestimated pressure gradient and severity of aortic valve dysfunction. The patient underwent cardiac catheterization with the intended goal of direct measurement of the transvalvular gradient and also to define the coronary anatomy in the event the patient required a third cardiac surgery. Anticoagulation was withheld for 1 day and the INR was 2.2 just prior to the procedure.

Transradial cardiac catheterization via the right radial artery access site was performed using standard techniques. An intra-arterial cocktail composed of verapamil 1 mg, nitroglycerin 100 ug, and heparin 2500 U was infused through the right radial artery after 5 Fr sheath insertion. Coronary angiography revealed the coronary arteries were patent with non-obstructive disease. The bi-leaflet aortic valve prosthesis was confirmed to be malfunctioning with one of the two leaflets visibly immobile by fluoroscopy. A 5 Fr Judkins Right catheter was positioned above the aortic valve. The catheter tip was placed near the sinotubular junction and the catheter remained above the valve to prevent interference with valve leaflet mobility. The FFR wire (PressureWire, Volcano Corporation) was safely advanced to the tip of the Judkins Right catheter. The tip of the FFR wire was then advanced under fluoroscopic guidance into the major orifice of the valve and then safely into the left ventricular cavity (Figure 1). Simultaneous hemodynamic tracings were then recorded for measurements of the left ventricular (LV) and aortic pressures. The LV and aortic pressures recorded were 200/10 and 105/60, respectively, making the peak gradient 95 mm Hg (Figure 2). After cardiac catheterization, hemostasis was achieved by using a TR band device (Terumo Corporation) for 4 hours. The use of the FFR guidewire enabled us to measure simultaneously and directly the LV and aortic pressures and the pressure gradient, which was critically important information in this patient facing a third, re-do sternotomy operation, with its attendant perioperative risks. Based on the above results, the patient was referred for a third aortic valve replacement surgery, which he underwent uneventfully.

Discussion

Hemodynamic assessment and direct, accurate measurement of LV and aortic pressures and the transvalvular pressure gradient are essential to assess mechanical prosthetic aortic valve function. When these measurements are derived from non-invasive Doppler assessments, they can sometimes be misleading, overestimated, or inconclusive. In the setting of both aortic and mitral mechanical valve prostheses, direct measurements can be technically complicated. Standard retrograde catheter access across a mechanical aortic valve prosthesis using a 0.035˝ diameter guidewire and pigtail catheter to access the left ventricle is feasible in a mechanical prosthetic aortic valve alone, but complications due to catheter entrapment in the minor valve orifice may be fatal. Accessing the left ventricle via transseptal puncture into the left atrium is not an option in the setting of a mechanical prosthetic mitral valve. Consequently, the only traditional approach to assess cardiac hemodynamics in the setting of both aortic and mitral mechanical prostheses is via direct, percutaneous LV apical puncture. Although transapical puncture for this indication has been well described, the major complication rates are estimated to be as high as 3-4%.¹

Very few case reports have proposed the use of guidewires indicated for coronary fractional flow reserve (FFR) assessment to evaluate the transvalvular pressure gradients and hemodynamic status of patients with both aortic and mitral valve mechanical prostheses.^2,3 The everyday use of these 0.014˝, low-profile, high-fidelity, intracoronary guidewires with a pressure transducer near the distal tip indicated for coronary FFR determination has led to growing indications for their use in other clinical circumstances that require simultaneous pressure measurements. Consequently, they may have a role in pressure gradient and hemodynamic assessments in the setting of double aortic and mitral mechanical prosthetic valves. 

The transradial approach to cardiac catheterization is gaining popularity worldwide. One significant advantage to the transradial approach in a patient with mechanical valve prostheses is the feasibility of performing a cardiac catheterization without stopping or interrupting anticoagulation. The feasibility and safety of pursuing cardiac catheterization without stopping anticoagulation using the transradial approach has been well documented.⁴ The case described in this report demonstrates the successful measurement of the transvalvular pressure gradient across the aortic valve in a patient with mechanical aortic and mitral prostheses using a coronary FFR guidewire via the transradial approach.

In their seminal article, Parham et al describe a case wherein the initial strategy to cross the inter-atrial septum to directly measure the LV pressures failed because of unsuccessful transseptal puncture.² Subsequently, positioning of a multipurpose catheter above the aortic valve enabled simultaneous LV and aortic measurements successfully using an 0.014˝ high-fidelity pressure monitoring guidewire. Also, in two other cases with simultaneous, successful transseptal puncture and direct LV pressure measurement, the LV pressure measurements from the pressure wire correlated with those of the direct measurements from the transseptal approach. In the same paper, they report an ex vivo experiment showing that FFR wire entrapment with bi-leaflet valves is very unlikely and requires >90° wire kink to cause resistance to wire withdrawal. Another case report by Khouzam et al reported a case in which a modern FFR pressure wire (PressureWire) was used to obtain complete hemodynamic assessments in the setting of both aortic and mitral prostheses, to evaluate for valvular stenosis and constrictive pericarditis, without the need for direct transapical puncture or repeat cardiac surgery.³

In the case presented here, we similarly report the use of a FFR pressure wire to obtain simultaneous, direct measurements of the LV and aortic pressures across a bi-leaflet mechanical aortic valve prosthesis in the setting of both aortic and mitral mechanical valve prostheses. We used the pressure wire measurements to confirm evidence of severe valve stenosis and dysfunction from non-invasive testing, without the need for direct transapical puncture and its inherent risks. The use of the pressure wire also allowed us to avoid the risks of acute damage of the already dysfunctional valve or catheter entrapment by traditional retrograde catheter access across a mechanical valve. Furthermore, we report the first case of the use of this technology for this indication via the radial artery access approach. This demonstrates yet another indication for transradial cardiac catheterization and our case adds to the growing body of literature in which transradial cardiac catheterization provides a significant safety advantage.

In conclusion, the pressure wire indicated for FFR determination may have a useful role in hemodynamic assessment and measuring transvalvular pressure gradients across prosthetic valves, especially in the setting of double aortic and mitral valve prostheses. The combination of this technique with transradial cardiac catheterization may have important advantages in mechanical valve patients in regards to the requisite anticoagulation.

References

1. Kern M. Mitral valve gradients — section IV: left ventricular puncture for hemodynamic evaluation of double prosthetic valve stenosis. In: Kern M, Lim MJ, Goldstein AJ, eds. Hemodynamic Rounds: Interpretation of Cardiac Pathophysiology from Pressure Waveform Analysis. 3rd ed. Hoboken, NJ: John Wiley & Sons; 2009:155-159.
2. Parham W, El Shafei A, Rajjoub H, Ziaee A, Kern MJ. Retrograde left ventricular hemodynamic assessment across bileaflet prosthetic aortic valves: the use of a high-fidelity pressure sensor angioplasty guidewire. Catheter Cardiovasc Interv. 2003;59(4):509-513.
3. Khouzam RN, Choi D, Naidu SS. Pressure wire for comprehensive hemodynamic assessment in a patient with mechanical aortic and mitral valves.  J Invasive Cardiol. 2010;22(11):555-556.
4. Hildick-Smith DJR, Walsh JT, Lowe MD, Petch MC. Coronary angiography in the fully anticoagulated patient: the transradial route is successful and safe. Catheter Cardiovasc Interv. 2003;58(1):8-10.

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From ¹the Division of Cardiology, Department of Medicine, NYU Langone Medical Center, New York, New York, and ²the Division of Cardiology, Department of Medicine, Beth Israel Medical Center, New York, New York.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Manuscript submitted November 7, 2011, provisional acceptance given December 7, 2011, final version accepted January 2, 2012.
Address for correspondence: Lori Vales, MD, New York Cardiovascular Associates, 275 Seventh Ave, Third Floor, New York, NY 10001. Email: lvalesmd@gmail.com