Took care of a patient who came to OR for a redo-sternotomy and triple valve replacement on ECMO.
Scroll down to see how we managed the patient’s possible HIT. The patient had a low score on her 4Ts assessment. Therefore, we opted to move forward before the functional assay came back with results as the patient was in dire need of triple valve replacement.
The goals of treatment for HIT are threefold: Interrupt the pathological immune response, inhibit the uncontrolled generation of thrombin, and minimize the complications.
Cessation of heparin alone does not sufficiently reduce the risk of thrombosis. The next step in management targets the uncontrolled generation of thrombin with the use of direct thrombin inhibitors (DTIs). Argatroban is preferred in patients with renal insufficiency, whereas lepirudin is the drug of choice for patients with liver disease. Bivalirudin is another hirudin analog that differs from lepirudin in that it is hemodialyzable and primarily undergoes enzymatic elimination. Its half-life is the shortest, 20-25 minutes, making bivalirudin the safest option since there are no reversal agents available.
All three agents can be monitored using the activated partial thromboplastin time (aPTT) to levels of 1.5 to 2.0 above baseline. Once the platelet count has increased to a minimum of 150,000/µL bridging therapy to warfarin is essential for the safe transition from DTIs.
Iloprost is a prostacyclin analogue that reversibly inhibits platelet aggregation. Plasma exchange was successful in reducing anti-P4/heparin antibodies and allowed for the restoration of a normal platelet count, essentially reversing the disease.
I have been utilizing ERAS in general surgery, OB, and ortho cases. Diving into one of my more tricky populations, I opted to see what ERAS practices are out there for cardiac surgery. Careful what you look for my friends. There’s actually a good amount of information out there!
There’s been a big debate re: who should care for LVAD patients… a general anesthesiologist or a cardiac anesthesiologist? See below for pros and cons of each. Ultimately, I think all anesthesiologists should be comfortable caring for these patients as we’ll see more and more LVAD patients undergoing procedures.
Goals of care for LVAD patients undergoing non-cardiac surgery should be directed at maintaining forward flow and adequate perfusion. Three main factors that affect LVAD flow are preload, RV function, and afterload.
The right ventricle is the primary means of LVAD filling; therefore, maintaining RV function is imperative.
Marked increases in systemic vascular resistance should be avoided.
Generally, decreases in pump flow should first be treated with a fluid challenge. Hypovolemia should be avoided and intraoperative losses should be replaced aggressively. Second line treatment should include inotropic support for the right ventricle.
Low-dose vasopressin (<2.4 U/h) may be the vasopressor of choice due to its minimal effect on pulmonary vascular resistance.
Standard Advanced Cardiovascular Life Support Guidelines should be followed; however, external chest compressions should be avoided during cardiac arrest.
Steep Trendelenburg may increase venous return, risking RV strain. Peritoneal insufflation for laparoscopic surgery also increases afterload and has detrimental effects on preload. Insufflation should utilize minimum pressures and be increased in a gradual, step-wise fashion.
TEE can be extremely valuable in diagnosing the cause of obstruction.
The other day we had a patient come in for a CABG. Aside for some coronary artery disease, hypertension, and chronic kidney disease, the patient was pretty healthy. They were not on anticoagulation prior to the procedure.
After I gave full dose heparin for going on bypass (41,000U in this case), the ACT only came up to 422. An additional 10,000U of heparin was given with a repeat ACT of 457. Still, our surgeon was not quite comfortable with that number and requested an additional 10,000U heparin. The ACT came to 477.
If the ACT stayed in the low 400s, would you go on bypass? What if the ACT had not responded to the repeated heparin dosings?
We ultimately decided to go on bypass. Repeat ACTs on bypass were in the 500s. No antithrombin was given. After separation from cardiopulmonary bypass and administration of protamine, repeat ACT was 111. Protamine was dosed accordingly to heparin administration and ACTs while on bypass.
A couple of weeks ago, I took care of a patient who desperately needed to get better from acute CHF. At that time, we placed the patient on an impella… but the next day, it was deemed that he needed ECMO to reperfuse his organs. After a week on ECMO with continued impella support, ECMO was titrated down and off while maintaining 3.9L/min flow from the impella. During the wean off ECMO, the patient had been extubated and was mentating clearly and interacting appropriately.
Fast forward a couple days after getting extubated, the patient was ripe for an LVAD. But which one? (We ended up placing the patient on HeartWare LVAD).
ENDURANCE trial: Randomized patients eligible for DT 2:1 to the HeartWare centrifugal flow LVAD versus the HeartMate II axial flow LVAD. The trial did reach its primary noninferiority endpoint of stroke free survival at 2 years (55.0% in the HeartWare patients versus 57.4% in the HeartMate II patients). Of note, a change in the design of the HeartWare device during the trial (sintering of the inflow cannula) appeared to decrease the incidence of pump thrombosis. Overall, the stroke rate was higher in the HeartWare arm whereas device malfunctions requiring exchange or urgent transplantation were more common in the HeartMate II arm. Data analysis suggested that better blood pressure control in the HeartWare arm may decrease the stroke rate and a second cohort of patients is being enrolled with more attention being paid to blood pressures management.
ROADMAP study: (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Heart Failure Patients) was an observational study of the Thoratec HeartMate II LVAD compared to optimal medical management in patients with advanced heart failure. Thirty day mortality was the same in both groups (1%) while one year survival was 80% in the LVAD group compared to 64% in the medical group (on an as treated basis). Functional status and quality of life improved significantly more in the LVAD group (analyzed by 6 minute walk, health related quality of life, and NYHA class). Unfortunately, adverse events in the LVAD group remained similar to what was previously reported in the DT trial, with bleeding being the most frequent adverse event.
“There’s an emergent case coming for impella placement.”
Impella? I’ve read about these devices and I’m familiar with managing patients on LVADs as well as providing anesthesia for LVAD placement. But, I’ve never done an Impella on a critically unstable patient.
Our hospital is starting to do more left atrial occlusion devices for people who have afib and aren’t able to tolerate blood thinners. Currently, two types are offered by our cardiologists: Watchman procedure (endocardial) vs Lariat procedure (epicardial).
It look and acts similar to a lariat or lasso. An external guide wire with a magnet at its tip is introduced outside the heart towards the left atrial appendage (LAA). Another wire with a magnet at its tip is introduced from a groin vein and it traverses the interatrial septum to sit at the most distal point inside the LAA. The magnets “connect” and the lariat is introduced along the external guide wire and essentially lassos the LAA.
A large occlusion device is inserted via a groin vein and traverses the interatrial septum into the proximal (base or largest opening) left atrial appendage. The device gets deployed and successfully occludes the LAA.
CONCLUSION: The Lariat device is associated with a lower rate of leaks at 1 year as compared with the Watchman device, with no difference in rates of cerebrovascular accident. There was no correlation between the presence of residual leak and the occurrence of cerebrovascular accident.
For these cases, we typically have a good flowing peripheral IV and intubate these patients for general anesthesia. There’s a fair amount of TEE required for placement and verification of correct positioning of the device. Both procedures require transseptal access. Watch for hypotension as there is a risk for pericardial effusion.