Case Studies In Small Animal

Cardiovascular Medicine

Case 21

Subsequent Examinations (notes taken from the case record)

Two Days After Discharge

Freckles is looking clinically better today. A brief echo of his heart revealed spontaneous
contrast in his left atrium. Blood was drawn for a prothrombin time (PT) and results were 9.7 seconds (still within the normal range). Freckles warfarin dosage was increased to 0.75 mg PO SID. Heparin was discontinued as of this morning.

Five Days After Discharge

A brief echo showed persistent spontaneous contrast in the left atrium. PT is 13.4 s which is still within the normal range, but is longer than when tested two days ago.
Conclusions: Freckles is clinically continuing to do well. He has not shown any signs of
thromboembolism, but is still at risk since there continues to be spontaneous contrast in his left atrium. His PT has increased from last time, but is still not prolonged. Warfarin can take up to a week to reach steady state, so we will leave him at the same dosage and retest his PT in a couple of days.

Ten Days After Discharge

ECHO: An echocardiogram of Freckles heart showed a very large clot in his left auricle. There is also spontaneous contrast in his left atrium. Freckles PT is 98 seconds. This is severely prolonged.
Conclusion: The clot in Freckles left auricle is very large and will likely break free at some point. It will most likely lodge somewhere in his heart as it is too large to leave. This will result in sudden death. The owner was informed of the possibility of sudden death and of the presence of the clot. We have decided to stop his warfarin therapy since it has not effectively prevented thrombus formation and has severely prolonged his PT and recheck him early next week. Depending on his PT at that time, the warfarin therapy may be restarted at a low dose. However, since the current thrombus obviously formed during warfarin therapy, warfarin is obviously ineffective in this cat.

A right parasternal short-axis view of the aorta (AO) and left atrium (LA). There is a large thrombus (arrowheads) in the left auricle that has formed despite warfarin therapy and despite the fact that the prothrombin time in this cat was markedly prolonged.

Two and one-half Weeks After Discharge

PT: 11.6 sec (WNL).
Echo: The left atrial thrombus remains in the position in the auricle as noted last week.
Spontaneous contrast persists. Mild pericardial effusion is present and the original
pericardial/auricular thrombus is noted. Mild pleural effusion is also noted.
Conclusion: The pleural effusion might be due to heart failure or to hemorrhage as a result of the previous PT prolongation. Thoracocentesis was not performed since at the time, PT results were not known. Hemorrhage would be expected to be quickly resorbed especially since the PT is now within normal limits and thus CHF is suspected.
Rx: Continue atenolol and enalapril at current doses. Increase Lasix to 12.5 mg PO BID. Institute aspirin 81 mg every third day. Recheck next week.

Three and one-half Weeks After Discharge

This last week, Freckles has lost weight, seems lethargic and is not eating well. The owner believes this started with the start of aspirin therapy.

Echo: persistent spontaneous contrast and left atrial thrombus. Moderate pleural effusion
present.
Pleurocentesis: 50 mls of pink/chylous effusion were obtained during oxygen supplementation.
Freckles became very easily stressed and more fluid could not be obtained without risk.
Conclusion: The most likely explanation for Freckle's clinical deterioration is progression of his disease. However, the owner wished to take him home and see how he did off the aspirin.
Phone message 3 days later: Freckles has rebounded. He is eating and drinking very well. He is very active and is breathing well. Most of his clinical signs may have been due to the pleural effusion although aspirin administration cannot be ruled-out as a cause. Schedule recheck next Tuesday.

Four and one-half Weeks After Discharge

This past week Freckles has been doing better, eating well and more active. He has shown more respiratory effort however.

Thoracocentesis: 220 mls chylous fluid removed.
Echo: Minimal fluid remaining post-tap. Left atrial thrombus unchanged.
Freckles will return for a recheck when his respiratory rate increases indicating a return of
fluid.

Seven Weeks After Discharge

Freckles has HCM. He is on atenolol 6.25 mg BID, enalapril 1.25 mg PO SID, and Lasix
12.5 mg PO BID. The last few days his respiratory effort has been slightly increased.

Echo: the left atrial thrombus is unchanged in size and is still attached to the wall, however it appears to have some mobility.
Pleurocentesis: 110 mls serosanguinous fluid removed.
Plan: Increase Lasix to 18.75 mg PO BID. Owner will continue to monitor for recurrence of effusion. The risk of the thrombus dislodging from the left auricle exists.

Ten Weeks After Discharge

Freckles respiratory rate is increased again. The echocardiogram revealed that there was no thrombus present in the left atrium today. He has shown no signs of systemic thromboembolism. 140 mls of fluid was removed from the pleural space.

Eleven Weeks After Discharge

Freckles is currently on Lasix 18.75 mg PO BID, enalapril 1.25 mg PO SID, and atenolol BID. The owner feels that he is dehydrated lately and he has not eaten well or had his normal energy level in the last few days. She was advised yesterday to discontinue the Lasix until the recheck today. She did that and Freckles ate well today. No increased respiratory effort or rate noted.

HR 160, irregularly irregular, mm pale gray/pink, femoral pulses weak, approximately 8% dehydrated by skin turgor and mm moistness. Abdominal palpation WNL. Extremities slightly cool.

Echo: a new thrombus is visualized in the left atrium. Severe pleural effusion noted and 175 mls chylous effusion removed.
Renal panel: Mild hyponatremia (147), hypokalemia (2.8), hypochloremia (107), metabolic alkalosis (TCO2 28), and mild azotemia (BUN 45, creatinine 2.2). The electrolyte abnormalities are due to a combination of volume expansion secondary to RAAS activation, diuretic therapy, and inappetence. Azotemia is unchanged from previous values and likely represents chronic renal disease in combination with diuretic therapy. Azotemia may have been worse several days ago prior to discontinuation of Lasix.
Rx: Start Tumil K (potassium supplement) at 2 mEq PO BID. Recheck renal panel in 1 week. Discontinue Lasix until Thursday then reinstitute at 12.5 mg PO BID if Freckles is again eating and drinking well. The owner will call if he doesn't improve.

Twelve Weeks After Discharge

Freckles has severe HCM with secondary pleural effusion. He is on Lasix 12.5 mg PO BID, atenolol 6.25 mg PO BID, and enalapril 1.25 mg PO SID. Last week he was dehydrated and hypokalemic. Lasix was discontinued for 2 days and reinstituted at 12.5 mg PO BID and potassium supplemented at 2 mEq BID. He was doing better but as of yesterday the owner feels he is not doing well and is having trouble breathing.

PE: Tachypneic with dull lung sounds ventrally. Depressed, cyanotic mucous membranes. Cachectic. Irregularly irregular HR 160 bpm. Poor femoral pulses.

220 mls chylous effusion removed from pleural space. Freckles appeared improved
following this. His RR came down, color improved and he ate some food.
Renal panel: static azotemia. K+ 3.6 (low end of normal range). Recommend continuation of K supplement at a lower dose if Freckles eats well (0.5 mEq BID).

Thirteen Weeks After Discharge

Freckles has severe HCM with secondary pleural effusion. He is here for a recheck of the pleural effusion. The Lasix dose was increased to 18.75 mg PO BID again at the last recheck. He has been doing well at home.

Lung sounds dull ventrally. Cat is eupneic. Cachexia. HR 160 irregularly irregular. Mm pale pink.

105 mls chylous effusion drained from the pleural space. The left atrial thrombus remains large and mobile with significant slow spontaneous contrast.
Recommend continuation of higher Lasix dose and recheck next week.

Fourteen Weeks After Discharge

Freckles has HCM. He is on Lasix, enalapril and atenolol. He recently has had
thoracocentesis on a weekly basis. Last week complete drainage could not be attained due to flocculation of fluid likely secondary to its chylous nature.

Echo: The left atrial thrombus appears subjectively larger than last week with little area for flow around into the LV. A picture was not taken because Freckles seemed clinically fragile and the echocardiogram had to be done while he was standing. A large amount of pleural effusion is noted and 140 mls of chylous effusion was removed. Only a small amount remained.

Fifteen Weeks After Discharge

Freckles has HCM and is on atenolol, Lasix and enalapril. He has needed weekly
thoracocentesis and is here for a recheck.

HR 150 bpm irregularly irregular. Mm pale pink, Dull lung sounds ventrally. Extremities
warm. Very thin

160 mls chylous effusion removed via thoracocentesis. LA thrombus unchanged.

Sixteen Weeks After Discharge

Phone Conversation: Freckles was doing well. The owner went to the store and when she came home he was dead, lying peacefully in the hallway (i.e., he died suddenly). The owner buried Freckles in the back yard.

Summary

Freckles lived for four months with severe cardiac disease and a large left atrial thrombus that came and went. No one expected him to live this long but he, his owner, and Dr. Adin hung in there. The results exceeded all expectations. His outcome, however, should in no way be used to predict the outcome of any other cat with the same disease processes. Many cats that present with a saddle thromboembolus die soon after or later of this complication, die from their heart disease, or are euthanized. Almost all cats that have a large left atrial thrombus do poorly and die of complications. Freckles was a "miracle" cat. One of those patients that defied the odds for much longer than expected.

©Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.