Contact Dr. Lindquist for consultation 1-800-838-4268 or info@sonopath.com
Skip to main content

Mitral Valve Repair in a 12-Year-Old FS Yorkshire Terrier Mixed Breed: Our Case Of the Month December 2017

Patient Information

Age
12 Years
Gender
Female, Spayed
Species
Canine

Images

Pre-surgical M-Mode: M-Mode imaging of the left ventricle shows severe volume overload (Cornell-Index 2,4). The left ventricular free wall is still moving and left ventricular systolic diameters are borderline normal (Cornell-Index 1,13).
Cannulation of the cervical vessels for connection to the heart lung machine.
Preparation of the aortic root for insertion of the cardioplegia cannula.
The left atrium is opened and suction tubes are inserted.
Mitral valve repiar: the artifical chordae are fixed to the papillary muscles and passed through the free edges of the valvular leaflets in a way that allows for proper coadaptation.
Mitral valve repair: The artificial chordae are tied down to the leaflets. It is extremely critical to adjust the chordae to the appropriate length to achieve a good valvular function.
Post-op mitral valve: The coadaptation of the mitral valve leaflets is optimal in this case.
Post-op M-Mode: Systolic function is good, the amplitude of the septum and free wall is typically similar.
Pre-operative thoracic radiograph shows significant cardiomegaly.
3 months post-operative thoracic radiograph shows a marked decrease in the size of the cardiac silhouette.
Picture at 3 months post-op. The patient is doing very well today! :)

The Austrian MacGyver Dr. Peter Modler is at it again repairing mitral valves in failing hearts in Europe. A veterinary cardiac surgeon with the "heart" of a pioneer, Dr. Peter Modler of Traunkreis Veterinary Specialists, Sattledt, Austria is featured in our December SonoPath Case of the Month.

History

The patient was presented for a pre-surgical cardiac evaluation. The patient was suffering from a rapidly progressing degenerative mitral valve. At the time of presentation the patient was on a regimen of Furosemide (8mg/kg/SID), Pimobendan (0.25 mg/kg/BID), Benazepril (0.25 mg/kg/SID), and Spironolactone (2mg/kg/SID). Despite her treatments, she was still experiencing exercise intolerance, mildly increased resting respiratory rate, and was coughing. Thoracic radiographs showed severe cardiomegaly, an increased lung opacity due to a bronchio-interstitial pattern, elevation of the trachea with possible left mainstem compression (possible airway collapse) and mildly dilated pulmonary veins.

Image Interpretation

The left ventricle appeared severely dilated. However, systolic function seemed to be only mildly impaired. Both mitral valve leaflets showed a significant prolapse and thickening. Chordal rupture affecting the anterior leaflet was visible. The left atrium was severely enlarged. Mitral inflow profiles revealed significantly increased filling pressures and volume overload. Mild tricuspid regurgitation due to valvular degeneration was also visible. Systolic pressure gradients across the tricuspid valve indicated moderate pulmonary hypertension (50 mm Hg).

DX

Rapidly progressing degenerative mitral valve.

Outcome

Open heart mitral repair was performed with the patient connected to an extracorporal circulation (heart lung machine). First, the cervical vessels (carotid artery and jugular vein) were prepared for cannulation. Next, a left 5-intercostal thoracotomy was performed and the pericardium was opened. The aortic root was freed from surrounding fat and prepared for insertion of the cardioplegia cannula. After administration of heparin, the cervical vessels were cannulated and connected to the extracorporal circuit (partial bypass). The cardioplegia cannula was inserted into the aortic root, followed by cross-clamping of the aorta and instillation of the cardioplegic solution (potassium solution for initiation of cardiac arrest and myocardial protection – full bypass). The left atrium was opened and suction tubes were inserted. After thorough inspection of the valve leaflets, artificial chordae were attached to the papillary muscles and then passed through the leaflet margins. A circumferential annuloplasty was performed in order to obtain an appropriate annular size. Therefore, pledgets were used to prevent the sutures from rupturing through the annular tissue. Afterwards, the chordae were adjusted to the appropriate length and tied. The left atrium was closed, vented, and the cross-clamp was removed. After a few seconds, the heart started with rhythmic contractions. The bypass was reduced and finally stopped, the cannulas were removed and hemostasis was re-established with protamine. Finally, the chest was closed over a chest drain which remained in place for the first 12 hours. The patient woke up uneventfully and was able to walk 5 hours after the end of surgery. Post-surgical echo showed good cardiac function and only mild mitral regurgitation. After more than 9 months post-op, the patient is still doing well.

Comments

The first days after surgery were challenging for the intensive care team because the patient was suffering from significant airway collapse which became more evident due to the increased post-surgical respiratory effort. Still, the patient stabilized and was finally released from hospital without any need for diuresis. The patient received Sildenafil for the first month to decrease pulmonary resistance, along with antibiotics and NSAIDS as routine post-op treatment. Theophylline was initiated as well to address the chronic airway disease.

*To see Dr. Modler's other Case Of the Month mitral valve repair, please click on this link: https://sonopath.com/resources/cases-month/mitral-valve-repair-due-severe-dmvd-6-year-old-cavalier-king-charles-spaniel-o

 

Videos

Pre-surgical echo: Severe left sided volume overload due to severe degenerative mitral valve disease is clearly visible.
Open heart mitral valve repair: A mitral valve repair surgery takes usually between 5 and 7 hrs in total. This video shows the most important steps of the patient's surgery.
Post-op echo: Left ventricular dimensions have normalized, systolic function is good. The mitral valve leaflets show a proper function.