Surgical LV vent
Surgical Technique – insertion of apical left ventricular vent
by Prof David McGiffin
The patient is placed with a 30-degree bump on the left side. The incision is a short left anterolateral thoracotomy with the interspace determined by the size of the heart. It is considerably better to be lower than necessary because if the thoracotomy is at the same level or higher than the apex of the left ventricle, it can be awkward placing the sutures.
Usually, the chest is entered through the upper border of the 6th or 7th rib. The pericardium is opened (A), the apex is then determined by indenting with a finger and watching the transoesophageal echocardiogram. Two 0 Ethibond mattress sutures with large pledgets are placed in an orthogonal position. If there is any chance the patient is to proceed to require a temporary left ventricular assist device, I use a 28Fr lighthouse tip cannula so it can be directly converted to a temporary left ventricular assist device. Alternatively a 24Fr cannula may be used.
Placement of LV drain
Make an incision, two interspaces below the thoracotomy, tie a finger of a glove over the end of the 28Fr cannula, and pull it through to the pericardium (C). Make a stab incision with an 11 blade between the Ethibond sutures and I use a series of Hegar dilators (D) to enlarge to hole (if there is a lot of scar this manoeuvre is absolutely necessary) and I also do this to make categorically sure if there is a friable myocardium, there is no chance of creating a false passage in the muscle. The position of the dilator in the LV is confirmed echocardiographically. When the hole is big enough the cannula is pushed through the ventricular hole, positioning the tip level with the base of the papillary muscles.
A ⅜” -¼” connector is then used to connect the cannula to a ¼” tubing (F), and plumbed via a ⅜”- ⅜”- ¼” connector into the access line, about 15-20 cm distal to the access cannula connection (G). After the orthogonal sutures are tied, I wrap the ends of the suture around the cannula and tie them, ensuring it is absolutely secure. I close the pericardium and place a Blake drain to the pericardial cavity posteriorly and a regular chest tube to the left pleural space, finally closing the thoracotomy in the usual way.
Imaging of the LV vent
Echocardiography TTE and TOE are well suited to image the LV vent in the LV intraoperatively as well as in Intensive Care.
Transaortic LV vent
Transaortic LV venting (‘pigtail’) is primarily used in selected ECPR patients.
Summary printout for transaortic LV venting to use in cath lab/ at the bedside
LV vent placement
The currently used catheter can currently only be inserted in the cath lab by the procedural cardiologist under fluoroscopy guidance.
Note: the catheter used (Cordis 8Fr XB3SH) is a specific coronary access catheter with 2 side holes – ‘pigtail’ appearance. ONLY if this catheter is not available a conventional 7Fr pigtail may be used.
The catheters are stored in the cath lab. It can ONLY be placed via the femoral artery, introduction via the radial access is NOT acceptable. Once placed in the mid-cavity of the left ventricle, the position of the catheter should be fixed, measured and documented. The connection to the ECMO circuit is the responsibility of the intensivist and described below.
- LV vent pack containing:
- Y connection ⅜ – ⅜ -¼
- ¼ LV vent tubing
- 50ml luer lock syringe to prime
- 3-way tap
- 2 bladder syringes + sterile drapes (alternatively included in ECMOpack)
- 3 ECMO clamps
Steps for Integration of LV vent into access limb of the ECMO circuit
Prepare connector – sterile
- Cut ¼ inch LV vent tubing to minimal length required to reach from pigtail catheter to 15-20cm below access cannula connection
- Push tubing onto ¼ inch end of Y-connector
- Make sure tubing is advanced at least 3mm beyond first ridge to allow application of cable tie later
- Prime tubing by connecting a 50ml luer lock syringe via a 3-way connector apply clamp on primed ¼ inch limb
Splice into access circuit
- Sterile preparation to clamp circuit 15-20cm below access cannula connection
- Clamp by a hand width above and below the intended cut
- Ensure the Y connector is inserted the correct direction with the single arm towards the console
- Perform underwater water seal for final connection – no air in connector
- CLAMP must be on ¼ side arm
- Remove clamps and go back on support
Connect ‘pigtail’ catheter
- Aspirate pigtail catheter, ensure flow
- Connect tightly to luer lock side arm
- Remove clamp and observe flow
- Cable tie 3 connections of Y-connector
- Attach separate ¼ flow meter probe to monitor flow
All patients require the medical management steps of LV distension syndrome and require dedicated ECMO review upon return to ICU. Patients without return of pulsatility within 12 hours need to be evaluated regarding the need to advance to a surgical LV vent. This should be concluded within hours and may require intervention overnight. Alternate causes of loss of pulsatility need to be considered in parallel such as hypovolaemia and bleeding.
Mandatory for patients who receive transaortic LV venting
- Flow meter attached to the ¼ inch tubing to monitor for clotting of the access limb
- Favouring heparin anticoagulation
- Early removal of catheter if clotting occurs
- Reassess and aim to remove after the first 12 – 24 hours
- Optimise medical management for LV distention
Removal of the ‘pigtail’ catheter once clotted should occur timely in ICU. The prefered method is to replace the Y-connector with a straight ⅜ connector.
The ¼ inch tubing needs to be clamped FIRST before removing the catheter through the sheath.
- Prepare a sterile field
- Clamp the ¼ inch tubing of the sidearm first then disconnect from the ‘pigtail’ catheter
- Apply red caps to both sides and leave the clamp on
- The ‘pigtail’ catheter can be removed through the sheath
- Prepare for the exchange of Y-connector to a straight ⅜ connector
- Clamp a hands width above and below the Y-connector, cut the connector out with minimal wastage of tubing
- Insert the ⅜ straight connector with appropriate underwater seal and resume ECMO support